Biostratigraphy of the Akiyoshi Limestone Group, Southwest Japan

Home , Exigua, Fusulinacea, Schwagerinidae

Bull. Kitakyusku Mus. Nat. Hist., 16: 1-97. March 28, 1997

Middle Carboniferous and Lower Permian Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Southwest Japan. Part I

Yasuhiro Ota

Department of Earth and Planetary Sciences, Faculty of Science, Kyushu University33, Hakozaki, Fukuoka 812,Japan (Received October 31, 1996)

Abstract The Akiyoshi Limestone Group, oneof the most representative stratigraphic standards ofJapanese Carboniferous and Permian, is widely distributedin the Akiyoshi Terrane, Southwest Japan. TheJigoku-dani area, the main area for investigation, is located in the northwestern part of the Akiyoshi Plateau, where the Middle Carboniferous and Lower Permian limestones are widely exposed. They are mainly composed of micritic limestones, indicating a lagoonal facies, in the relatively low energy environments within the Akiyoshi organicreefcomplex. The limestones are alsocharacterized by abundant and well-preserved fusulinaccans, and the following nine zones including seven subzones, were recognized in ascending order as: 1. Fusulinella biconica Zone, 2. Fusulina cf. shikokuensis Zone: 2-1. Fusulinella cf. obesa Subzone, 2-2. Pseudofusulitulla hidaensis Subzone, 3. Obsoletes obsolelus Zone: 3-1. Protriticites toriyamai Subzone, 3-2. Protriticites matsumotoi Subzone, 4. Montiparus sp. A Zone, 5. Triticites yayamadakensis Zone: 5-1. Triticites saurini Subzone, 5-2. Schwagerina sp. A Subzone, 5-3. Triticites biconicus Subzone, 6. Schwagerina (?) cf. satoi Zone, 7. Pseudoschwagerina muongthensis Zone, 8. Pseudqfusulina vulgaris globosa Zone, 9. Pseudofusulina afi". ambigua Zone. The distribution of these fusulinacean zones shows well the inverted structure of limestones in this area. The second investigated AK area is located in front of the Akiyoshi-dai Museum of Natural History, where limestones with nearly complete successions of the Middle Carboniferous to Lower Permian are well exposed. The following fusulinacean zones are discriminated alonga measured traverse, in ascending order:Pseudofusulinella hidaensis Zone, Protriticites matsumotoi Zone (s. I.), Montiparus sp. A Zone, Triticites simplex Zone (s. 1.), Pseudoschwagerina muongthensis Zone, and Pseudofusulina vulgaris Zone. Of them, Protriticites matsumotoi Zone (s. I.) is tentatively subdivided into the lower Protriticites matsumotoi Zone (s. s.) and the upper Quasifusulinoides sp. A Zone. Triticites simplex Zone (s. 1.) is tentatively subdivided into the lower Schwagerina sp. A Zone and the upper Triticites simplex Zone (s. s.). Limestones in this area mainly consist of alternation of micritic limestones and those with sparry calcite matrices. The facies of limestones indicate that they represent a marginal lagoon paleocnvironment. The limestones in this area explain the two sequences. The third investigated area, Mt. Maruyama, contains Middle and Upper Carbo niferous limestones. They represent a sedimentary environment of reef flat or bypass margin between the fore reef and open sea. They yield the primitive types ofthegenus Protriticites, i.e., Protriticites yanagidai Ota, Protriticites masamichii Ota, and Protriticites Yasuhiro Ota

toriyamai Ota. From viewpoints of their morphological characters and affinities, Protriticites yanagidai Ota represents a primitive stage in the phylogenetic line between Protriticites yanagidai Ota and Protriticites matsumotoi (Kanmera), whereas Protriticites masamichii Ota is likely to be a transitional species to Montiparus matsumotoi injlatus, reported by Watanabe (1991). Based on these fusulinacean assemblages and phylogenetic considerations, it is concluded that the variation of elements among fusulinacean assemblages is caused by change of lithofacies in development of the Akiyoshi organic reef complex. It has a large influence in recognition of the biostratigraphic units. The palcoenvironmental analysis of the Akiyoshi organic reef complex is indispensable for establishment of the reexamined biostratigraphy.

Introduction

The study area is located in the Akiyoshi Terrane of Southwest Japan where the Middle Carboniferous to Lower Permian Akiyoshi Limestone Group is widely dis tributed. The Akiyoshi Limestone Group which contains well-preserved fusulinaceans and many other well-preserved mega-fossils is considered to have originally formed as an organic reef complex upon a basaltic mound. This paper describes the fusulinacean faunas and discusses the elements of the newly discriminated fusulina cean zones. It also examines the Middle Carboniferous to Early Permian fusulina cean phylogenetic transition in the Jigoku-dani area and two other related areas on the Akiyoshi limestone plateau. The principal survey area, Jigoku-dani, is located in the northwestern part of the Akiyoshi Plateau. Karst topography characterized by lapie field, is well developed and a valley with a NE-SW trend is located in the middle of the area. Middle Car boniferous to Lower Permian limestones with a number of well-preserved fusulinaceans, are widely distributed. Consequently, this area was first selected for the ex amination of the transition of the fusulinacean assemblages during Middle Carbo niferous to Early Permian. M. Ota (1977) suggested that the general strikes and dips of the Akiyoshi Limestone Group in the area are nearly horizontal. The author set a starting point at an altitude of 355 m, and carried out field observation and sampling of materials with a measuring tape. The measured traverses (JI Traverse) were mainly drawn by crossing the general trend of the strike and sometimes drawn by lines parallel to strike. Limestone samples were carefully collected along the measured traverses. The second investigated AK area was selected in front of the Akiyoshi-dai Muse um of Natural History. In this area, there are nearly complete successions of Car boniferous to Lower Permian limestones with abundant fusulinaceans. This area is also characterized by a lapie field. The third investigated area, Mt. Maruyama is located in the Isa Quarry, Mine City. A principal traverse was set and measured along the eastern slope of Mt. Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 3

Maruyama at an elevation of about 200 m with the following abbreviation as MA Traverse. This traverse was established by crossing the general strike of E-W trend at right angles. Limestones in this area are variable in their organic composition with rugose corals, ammonoids, phylloid algae, brachiopods and fusulinaceans occur ring alone or together. The lithologic facies of limestones and their fossil compo nents suggest that the paleoenvironment of this area was a reef flat or bypass margin between the fore reef part of the Akiyoshi organic reef complex and open sea (Fig. 1).

; m 1 Fig. 1. Simplified geologic map of the Akiyoshi area, showing locations of the investigation areas, Jigoku-dani area, AK area and Mt. Maruyama area. 1. Akiyoshi Limestone Group. 2. Beppu and Ota Groups. 3. Tsuncmori Group. 4. Cretaceous sedimentary and igneous rocks. 5. Major thrust. Yasuhiro Ota

Historical review

-I. Geology of the Akiyoshi Limestone The geology of the Akiyoshi Limestone and surrounding areas was first investi gated by Ozawa (1923), who established the biostratigraphy by the use of fusulina cean zones. He discovered the inverted succession of the fusulinacean zones and recognized the inverted sequences as an autochthonous recumbent fold caused by lat eral movement from south to north. Ozawa's interpretation was developed by Kobayashi (1935) and he proposed the Akiyoshi Phase for the first of the Mesozoic orogenic movements. Toriyama (1954a, b, 1958) reexamined the geology and fusulinacean paleontology of the Akiyoshi Limestone Group and the surrounding non-calcareous sedimentary rocks. He studied the Carboniferous and Permian fusulinaceans in detail and established refined fusulinacean zones on the Carbonif erous and Permian limestones. The fusulinacean zones by Toriyama (1963, 1967, 1978) had been treated as a standard of the Carboniferous and Permian biostratigra phy in Japan. Along with the biostratigraphic work, Toriyama showed his interpre tation on the geologic structure of the Akiyoshi Limestone Group. Later, Hasegawa (1958, 1963) and Murata (1961) showed different interpretations on the inverted structure of the Akiyoshi Limestone Group. Concurrently, a sedimentological study with the biostratigraphy, for the purpose of the paleoenvironmental examination had been started by M. Ota and others. Eto (1967) examined the bio- and lithofacies of the lower part of the Akiyoshi Limestone Group in the Okubo area. He analyzed biofacies of limestones and re constructed the sediment depositional process of limestones on the volcanic seamount. In 1968, M. Ota first suggested for the paleoenvironments of the Akiyoshi Limestone Group that it was formed as an organic reef complex on the basaltic seamount like an atoll of the present ocean. This is an epoch-making study from the viewpoint of paleoenvironmental analysis on the Akiyoshi Limestone Group. The detailed lithology of the basal pyroclastic rocks was examined and described by Yanagida, M. Ota, Sugimura and Haikawa (1971). They showed the sedimentary sequenceof the Akiyoshi Limestone in the Shishide-dai area with a columnar section and description of the biostratigraphy of the lowest part of the Akiyoshi Limestone Group. Schwan and M. Ota (1977) carefully reexamined the geologic structures of the Akiyoshi Limestone Group and surrounding non-calcareous rocks. They sug gested lateral and rotating pressures caused by gravity movement for the partly in verted succession of the Akiyoshi Limestone Group. The new interpretation for the tectonics of limestones and the surrounding non- calcareous rocks, based on the plate tectonic theory of the new global tectonics, was shown by Kanmera and Nishi (1983) and Sano and Kanmera (1988). They con sidered that the Akiyoshi organic reef was developed on a seamount of basaltic rock and then accreted to the terrigenous sediments of the Permian Tsunemori Formation Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 5 at the end of the Middle Permian. The following palaeontological and geological contributions are important for establishment of the biostratigraphy and comprehension of the accretionary process of the Akiyoshi Limestone Group: Fujii (1972); Fujii and Mikami (1970); Haikawa (1986, 1988); Haikawa and M. Ota (1978, 1983); Hasegawa (1967); Hashimoto (1979); Ichikawa (1984, 1990); Kawano (1960); Kimura, Hayami and Yoshida (1991); Matsusue (1986, 1988); Miura (1987); Nakamura and M. Ota (1974); Nishida (1971); Nishida and Kyuma (1982, 1984); M. Ota (1971); M. Ota, Toriyama, Sugimura and Haikawa (1973); N. Ota, Sugimura and M. Ota (1969); Sakagami (1964a, b); Sakagami and Sugimura (1978, 1983); Sano, Iijima and Hattori (1987); Sano and Kanmera (1991a, b, c, d); Sugimura (1972, 1974, 1985); Sugimura and M. Ota (1971, 1980); Sugiyama (1984); Uchiyama, Sano and Kanmera (1986); Ueno (1991a, b, c); Yanagida (1962, 1965, 1968, 1973, 1979, 1983); Yanagida, M. Ota and Nagai (1977); Yamagiwa and M. Ota (1963).

-II. Middle Carboniferous to Lower Permian biostratigraphic units in the Akiyoshi Limestone Group The fusulinacean biostratigraphy of the Akiyoshi Limestone Group has been treated as a standard of the Japanese Carboniferous and Permian. Recently, the chronostratigraphic units of the Middle Carboniferous and Lower Permian have been very often discussed in the world to confirm the exact boundary between the Carbon iferous and Permian. The Middle Carboniferous to Lower Permian biostratigraphic units in the Akiyoshi Limestone Group also have been discussed by many workers, such as, Ozawa (1923), Kobayashi (1935, 1941), Sugiyama (1939), Toriyama (1954a, b), Hasegawa (1958, 1963, 1988), Murata (1961), M. Ota (1968, 1977), Ueno (1989), Ishii (1990), Ozawa and Kobayashi (1990), Watanabe (1991), and Y. Ota and M. Ota (1993). In case of the Akiyoshi region, it is well known that the Akiyoshi Limestone Group was formed as an organic reef complex and that there is a great variation in the biofacies and lithofacies. Consequently, in the Akiyoshi Limestone, the fusulina cean assemblages of the same age often show different constituents with different types of the limestone, suggesting different paleoenvironments (M. Ota, 1977). Therefore, it is indispensable to carefully discern the paleoenvironment in the Akiyoshi organic reef complex to establish the standard fusulinacean zones in the Akiyoshi Limestone Group. A number of stratigraphic units of the same age with different leading fossils are known in the Akiyoshi Limestone Group. It is understood that the complicated state ofzonation might be caused by differences ofthe original habitats of biota in the organic reef complex. For instance, Ozawa and Kobayashi (1990) proposed 47 fossil zones in the Akiyoshi Limestone Group. However, these zones are generally not mappable and some fossils are not included in these zones (e.g. Sugiyama and Haikawa, 1993). These finely distinguished zones, appear to be reasonable, how- 6 Yasuhiro Ota ever they are sometimes not practical. A careful examination of the lateral and vertical distributions and transitions in the biofacies and lithofacies is required so as not to disregard the original habitats of biota in the various types of limestones. Watanabe (1991) discussed the inflated schwagerinids and proposed some phy logenetic lineages and datum levels among them. His proposals are very interesting and logical. The inflated schwagerinids are well known in world wide distribution. Therefore they are very useful for international correlation. For establishing the chronostratigraphic units, the reconstruction of the evolutionary trend of the inflated schwagerinids is indispensable. On the other hand, the inflated schwagerinids are also known to occur in specialized environments of deposition, that show apparently imbalanced distribution of them, near the Carboniferous and Permian boundary (Ross, 1964). Therefore, special attention and examination of the constituents of the inflated schwagerinids are essential to establish the standard of both logical and practical chronostratigraphic units in the local area. Details of examination and comparison of the biostratigraphic units are discussed in the following chapters.

Research on the chronostratigraphic units near the Carboniferous-Permian boundary

The chronostratigraphic divisions of the Carboniferous and Permian have been discussed for many years in and outside Japan. The definition ofthe Carboniferous- Permian boundary has received special attention. As the Carboniferous-Permian boundary is an intersystem boundary, defining the boundary means to establish the datum position in the rock sequences and this is essential for worldwide correlation. The name Carboniferous was derived from the coal bearing beds (Coal Mea sures) in England, whereas that of the Permian originated from the region of Perm, Russia. The Upper Carboniferous in England is mainly composed of terrigenous sediments. The Lower Permian in Russia, on the other hand, mainly comprises ma rine sediments. Therefore, it is not easy to confirm the boundary between the Car boniferous and Permian and to make intercontinental correlations of the Upper Carboniferous to Lower Permian successions. In general the Carboniferous-Per mian boundary is defined by marine sediments and fossils, which should be effective for the world wide correlation. From historical view points, the boundary should be defined in Russia. However, the Carboniferous and Permian boundary has been left ambiguously even in the type area. Therefore, it is true that many workers continue to apply their own definition. Here, careful considerations are summarized in three cases, relating to the boundary problems. (1). The first case is the incompatibility caused by treating the stratigraphic boundary as the chronostratigraphic boundary. This consideration has resulted from regarding faunal elements of different ages as being of the same age. Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 7

(2). The second case is the confusion caused by applying the personal defini tion of each worker for the Carboniferous and Permian boundary even in Russia. This trouble is also due to a key fossil which was chosen for defining the Carbonifer ous-Permian boundary in spite of the inexact state of its taxonomic position. (3). The third case is shown by applying the evolutionary stage of a fossil for defining the boundary. There are also some problems, because it is difficult to con firm the key fossil for defining the Carboniferous-Permian boundary. As mentioned above, each case includes complicated and unsolved problems, and arguments about the definition of the Carboniferous-Permian boundary have continued since Murchison first introduced the Permian in 1841. Some proposals are introduced as follows. According to Rauser and Shchegolev (1979), the Carboniferous-Permian boundary has been studied intensively since Murchison, and the highest stratig raphic unit in the Carboniferous, namely, the top of "Schwagerina" Horizon was widely recognized as marking of the Carboniferous-Permian boundary. However, after the Asselian Stage was established by Ruzhencev, some paleontologists argued that the Carboniferous-Permian boundary should lie at the base of the Asselian, namely, at the baseof the "Schwagerina" Horizon. Definitions of the boundary of the Carboniferous and Permian boundary have been summarized as follows. 1. Put the boundary between the Carboniferous and Permian at the base of the Daixina sokensis Zone of the Gzhelian. 2. Make the base of the Asselian the boundary between the Carboniferous and Permian. 3. Put the boundary at the base of the upper fusulinacean zone in the Asselian, (the base of Nenetsky Horizon). 4. Place the boundary at the top of the Asselian (Table 1). Rui and Zhang (1987) summarized the Carboniferous-Permian boundary in the world. According to them, six proposals for the Carboniferous-Permian boundary were shown even in Russia as follows. 1. The Carboniferous-Permian boundary is at the base of the Daixina sokensis Zone in the upper part of the Gzhelian Stage. 2. The base of the Daixina bosbylauensis-Daixina robusla Zone is the Car boniferous-Permian boundary. 3. The basal part of the Asselian Stage in Russia, namely, the Schwagerina vulgaris-Schwagerina fusiformis Zone is the lowest part of the Permian. 4. The basal part of the Schwagerina sphaerica-Pseudofusulina firma Zone of the upper part of the Asselian, namely, the lowest part of the Nenet Horizon is the lowest part of the Permian. 5. The Carboniferous-Permian boundary is between the top of the Asselian and the base of the Sakmarian, namely, between the Schwagerina sphaerica-Pseudofusulina firma Zone and the Pseudofusulina moelleri-Pseudofusulina uralica Zone. Yasuhiro Ota

Table 1. Correlation of the Carboniferous and Permian boundary among the main pro vinces (after Rauser and Shcheoolev, 1979).

USA Russian Camlc Platform &Ural Alps New W.Texas Kuma Mexfoo

Zone Formation Zone

1 si

Hi nil ft l!

6. The Carboniferous-Permian boundary is at the boundary between the Artinskian and Sakmarian (Table 2). In USA Beede and Kniker (1924) considered that "Schwagerina" was a good index fossil and its earliest occurrence mightbe safely regarded as revealing the basal part of the Permian. They proposed that "the zone of Schwagerina" (=Pseudo schwagerina of modern usage) should be recognized as the base of the Permian. Ac cording to the Permian Subcommittee of the National Research Council's Committee on Stratigraphy (Dunbar, Chairman) (1960), the U.S. Geological Survey officially recognized the Permian as a system in 1941. But it was uncertain until 1951 wheth er the Wolfcampian Series was "Permian". It is common that American geologists usually put the base of the Pseudoschwagerina Zone as the base of the Permian. They Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I

Table 2. Different levels proposed for theCarboniferous-Permian boundary in Russia (after Rui and Zhang, 1987).

Official Carboniferous - Permian boundary in Russia Raiser. 1960 Ruzherchev (Russian Platformand Ural) RertOnger. Rybakov. 1962 Lever), 1986 Barkhatova, and Lurryak. 1962 1969: Koar. 1884 1970 Movsrtovich. 1S66 Sarycheva, Horizon Zone 196S

Irgjn Parafusulinalutugtni Permian

Burtsyev Pseudofusulina ccncavutas

Styertttamak Pseudofusulina urdalensis

Pseudofusulina vemeuSi • £ Psf. uraBca Psf. moeBeriZ.

Pseudofusulina moeBeri

Schwagerina sphaerica - Nenet Pseudofusulina firma Horizon Carboniferous

Schwagerina moelleri• S. vulgaris. Pseudofusulina fecunda S. fusttcnnlsZ. Sokotiegor Dah&ia Schwagerina vulgaris • bosbyt&uoftsls D. robust* Z SfusHbrmis Carboniferous Carboniferous

Daixina Daixina sokensis sokensisZ.

JiguHtespgulensis Carboniferous have the opinion that the base of the Permian in the U.S. is essentially equivalent to the same horizon of the Russia (Fig. 2). Ross (1984) summarized Carbonifer ous-Permian fusulinaceans of North America and concluded that the base of the Asselian in the Russian type locality, namely, the base of the zone with large, inflated schwagerinids, was presently widely recognized as the base of the lowest Permian faunal zone by many invertebrate paleontologists in North America, Japan and south ern Europe. Wilde (1984) also published on the Carboniferous-Permian boundary and he discussed this problem from the viewpoint of fusulinacean taxonomy. He also remarked that the Carboniferous-Permian boundary had been drawn at the base of the Asselian Stage in Russia. In addition, he recognized the boundary as equiva lent to the middle Wolfcampian unconformity, identified in the type section of the Wolfcampian in the United States (Figs. 3, 4). In China, Rui and Zhang (1987) reviewed the current situations of the Car boniferous-Permian boundary. According to them, before 1970, Chinese workers traditionally regarded the top of the Pseudoschwagerina Zone in the Maping (Chuan- shan) Formation as the upper most of the Carboniferous, and the lower part of the Chihsia Formation, namely, the Schwagerina tschernyschewi Zone or the Misellina Subzone ofthe Parafusulina Zone as the lower most ofthe Permian. In 1981, Rui Lin found the "Carboniferous" (traditional Chinese sense)-Permian mixed fusulinacean 10 Yasuhiro Ota

U Jl i t i L ii

UJ 4 CD c < /'seudoschif/agerina a 1- co 1 z Pseudofusulina Parasch vagerina < a. Q. Schubertella Schwdgerina < LeptoWffc/tes w •V* .3 _i f § " ir ii ,, -J-

UJ CD 9 o < r- CO ? Pseudoi usulinella c z a < c "1 Dunba inella Tr/fii ;/fes > 5 >. a: V CO > c ' f c a> a © z •9 < 3 rr O CO CO Eowaeringella 1 ' Fig. 2. Approximate ranges of important fusulinacean genera near the Virgilian-Wolfcam pian boundary in the Big Hatchet Mts. (after Wilde, 1984; Rui and Zhang, 1987). fauna in the section of the "Carboniferous" to Permian continuous sediments above the uppermost PseudoschwagerinaZone or the Robustoschwagerinaschellwieni Zone of Permian age. This sequence seems to represent the Liangshan Member, and Rui advocated that the lower boundary of the Permian should be placed below this limestone sequence. Afterwards, some workers supplemented and revised the definition on the traditional boundary. At present 18 main proposals for the Chinese Carboniferous-Permian boundary are known (Rui and Zhang, 1987). These Chinese proposals have been continuously discussed and they are put into six main opinions about the definition of the Carboniferous-Permian boundary (Table 3). 1. Putting the boundary between the Carboniferous and Permian at the top of SchwagerinaZone, is known as the traditional boundary in China and used for more than 40 years. In short, the boundary is compared with the top of the Pseudo schwagerinaZone or the SphaeroschwagerinaZone, namely the top of the Maping Formation or the Chuanshan Formation, correlated with the boundary between the RUSSIA U. S. A. cr) Robustoschwagerina tumida, Parafusulina Robustoschwagerina stanislavi Pseudofusulina ex gr. vulgaris - kraffti 11 Parafusulina, Skinnerella Pseudoschwagerina Robustoschwagerina ex gr. tumidiformis 10 Chalaroschwagerina, Monodixodina

CD CD 1 c Q_ Schwagerina sphaerica co Preparafusulina i Cuniculinella

c Pseudoschwagerina robusta CD o 2 Pseudoschwagerina robusta Q. Q_ Schwagerina moelleri 8 E s CD Schwagerina vulgaris - fusiformis Pseudoschwagerina uddeni Occidentoschwagerina Q

Daixina Triticites - Schwagerina

ui Jigulites Triticites - Schwagerina

CD c Rauserites stuckenbergi Triticitesbeedei - moorei - plummeri eg c Dunbarinella, Waeringella, Rauserites? 'c o n i_ Triticites O CO Kansanella ohioensis - articus - irregularis Triticites ohioensis CO O c k_ c CD Triticitesplanus CD Q. Montiparus Q_ Q. Eotriticites u. D 0 Obsoletes - Protriticites Eowaeringella Q. Q. J3_ Fig. 3. Correlation of Carboniferous-Permian fusulinid zones between Russia and U. S. A. (after Wilde, 1984). 12 Yasuhiro Ota

4. Possible alternate correlation offusulinid zones, Russia-USA (after Wilde, 1984).

Asselian and Sakmarian Stages. 2. The Carboniferous-Permian boundary should be drawn at the base of the Pseudoschwagerina morsei- Robustoschwagerina xiaodushanica Zone, namely, the lowermost part of the Mapingian, characterized by the first appearance of the rapidly evolving pseudoschwagerinids (Zhou et ai, 1987, Fig.5). 3. The base of the Montiparus Zone is regarded as the lowest part of the Permian. The Montiparus Zone is characterized by the first appearance of the keriotheca in the wall microstructure (Zhang, 1984, Figs. 6, 7). 4. The Carboniferous-Permian boundary should be placed between the Late Carboniferous Nephelophyllum-Pseudotimania assemblage Zone and the Early Permian Kepingophyllum assemblage Zone, namely between the Shazitang Formation and the Longyin Formation of the Longyin section in Guizhou. However, Rui and Zhang (1987) noticed that the lowest partofthe Kepingophyllum assemblage Zone was higher than the base of the Pseudoschwagerina Zone. 5. The lowest part of the Pseudofusulina moelleri Zone and the Protopopanoceras Zone in the Longyin section of Guizhou, is correlated with the lowest Sakmarian in Russia and it is regarded as the lowest ofthe Permian. According to Ruiand Zhang (1987), this consideration of the Carboniferous and Permian boundary is ambiguous, because the Pseudofusulina moelleri Zone contains Sphaeroschwagerina and other charac teristic elements of the Asselian Stage. Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 13

Table 3. Different levels proposed to the Carboniferous-Permian boundary in China (after Rui and Zhang, 1987).

Locality Lower Permian Upper Carboniferous

Nanjing Mis Swine Limestone Member Chuanshan Fra Chen, 1934,Sheng.1962 MdaudaeZ 1 S. tschemyschewi Z PseudoschwaaerinaZ 1 TriMesZ Chinling Range YaziFra SanBchongFm. Wang etaL 1973 MiseSlmaZ. PamuinaZ PseudoschwacsrhaZ 1 TriMesZ L Permian Upper CarbonSerous Nanjing hits ChuanshanFm. Wang,1978 Swine L Mem. M. daudae Z .Sphaeroschwagerina moelleri Z 1 TriMesZ Lower Permian Upper CarbonSerous Puan,Guizhou ChBisia Fm. LiangshanFra Baomoshan Fra Longyin Fra I Shazitang Fm. Wuetal., 1979 Robust, Sphaeroschwagerina Z Triticites Z Yangel al.,1983 schellwieniZ Sph. domerosa ISph. constans Lower Permian" UpperCarboniferous SouthernJiang ChhsiaFm. ChuanshanFm. Yu.1981 Parawenl Z 1Chuanshan. Z 1 Yangzistratigraphic province Chftsia Stage MapingStage Rui,1981 Misellina Z PseudoschwaaerinaZ. 1 TriMesZ South China ChBisia Stage Maping Stage Sheng., 1982 M. daudaeZ 1Schwagerina tschemyschewi Z Pseudosc wagerina Z I Triticites Z Lower Permian Upper Carboniferous Puan,Guizhou Chihsia Stage Longyin Fm Shazitang Fra Zhang, el al, 1982 MiseSna daudae Zone Pseudofusulna moelleriZone Ps-ZelliaZ TriMesZ

ChBisia Fra ChannmoFra Mapina Fm Longlin, Guanga Misellina, Pseudofusul'ina inusilata- Long, 1982 TriMesZ Paratusulina Robustoschwagerina Z Pseudoschwagerina Z Longlin, Guangxi ChihsiaFm. LortfinStaae Maping Stage Huang, 1984 Misellina Z Pamtina- Nagatoella {Daivasies Pseudoschwagerina Z | Triticites Z ChBisia F. Southern Hunan Chuanshan Fm Zhou, 1982 M. daudaeZ Staffollal S.cushmaniZ Pseudoschwagerina Z Nanjing hBis ChBisia Fra Swine Limestone Fm. Chuanshan Fra Zhang, 1983 M. daudae Z Darvasites oidinatus Z Sphaeroschwagerina moelleri Z Triticites Z Proposal 1 Lower Permian U.Carb.

Southwestern Guizhou M daudae M. Psl.- Rob. Psl. moelleri- j TriMesZ Wuetal., 1983 Bed Rob. Rob. «£ schellwieni Q. Psl. fusiormis 1 N Proposal 2 Lower Permian U.Carb. Lower Permian UpperCarboniferous Puan,Guizhou ChBisia Fm. Uanoshan Fm. Baomoshan Fm Longyin Fm. | Shazitang Fm. Zhang, 1983 Rob. Sphmoschwaaerina Z. Triticites Z schellwieniZ Sph. domerosa\ Sph. constans Lower Permian UpperCarbonSerous Qinling Range YaziFra <* SanBchongFm. Ding etal., 1983 M.daudae Robustoschwagerina, Sphaeroschwagerina I <£ Shaa. Triticites Lower Permian Upper Carboniferous South China ChBisia Fm. Liangshan Fra | Baomoshan Fra| Longyin Fm. Shazitang Fm. Wu, etal., 1984 M daudae Z Kepingophyllum Assemblage =(P& Z.) Triticites Z

South China Permian Zhang, 1985 T.Z M.Z Lower Permian Upper Carboniferous Luodan, Guizhou ChihsiaFm. Nashui Fm. MapingFra Xiong etal, 1985 Pamirina Z Sphaeroschwagerina, Misellina Swoetognathus Pseudoschwagerina Triticites whiteiZ 14 Yasuhiro Ota

1. Protriticites subschwagerinoides Zone 2. Triticites montiparus Zone 3. Triticites schwageriniformis Zone 4. Triticites dictyophorvs Zone 5. Triticites shikhanensis compactus Zone 6. fteudaschwagerina mo/sej - Robustoschwagerina xiaodushanica Zone 7. fteudoschwagerina parabeedei - Sphaeroschwagerina sphaerica Zone 8. fteudoschwagerina robusta - Zellia chengkungensis Zone 9. Pseudofusulina vulgaris - U laxifusulina iniqua zone si 10. Chalaroschwagerina tumentis Zone J0.F I 11. Pamirinachinlingensis Zone

Fig. 5. Composite stratigraphic section, showing fusulinacean faunas near the Carbonifer ous-Permian boundary at Xiaodushan, Guangnan, Easter Yunnan (after Zhou et al., 1987).

6. The top of the Baomoshan Formation, namely the Robustoschwagerina Zone is correlated with the base of Artinskian Stage and it is regarded as the lowest part of the Permian in China. In Japan, the definition of the Carboniferous-Permian boundary also has been discussed for a long time in several important provinces by many workers. The author presents some recent considerations on this problem, by some workers in the Akiyoshi Limestone Group. Toriyama (1954a, b, 1958) divided the Akiyoshi Limestone Group into the following seven fusulinacean zones in descending order. Yabeina Zone Neoschwagerina Zone Parafusulina Zone Pseudoschwagerina Zone Fusulinella Zone Projusulinella Zone Millerella Zone He subdivided the Pseudoschwagerina Zone into two subzones, the upper, the Pseudofusulina vulgaris Subzone and the lower, the Triticites simplex Subzone. Then Japan RUSSIA USA South China Texas Northeast Southwest Darvas of Central Asia Transcaucas South Ural

Zone Zone Zone Stage Zone Zone Zone Zone

Neo- Nanklnella • Paralusulina Monodie- Misellina schwagerina Bolorian J Misellina M. claudiae xodina § simplex- parvicostata \Chalaro- Kungurian Paralusulina Paralusulina matsubaishi M. bngjinensis - M. prima Cancellina M. dyhrenfurthi ischwagerina

Darvasites Chalaro Parafusulina Pseudo- schwagerina soSdissima, Artinskian tusutina Misellina Yakhtashian vulgaris- concessa, acmeZ. Nagatoella Pamirina schellwieni Pseudo- lusulina Psl. urdalensis Robustoschwagerina schellwieni Robusto Psl. callosa, (or StatiellarichZone)- Pseudo- schwagerina iusulina Sakmarian Sakmarian Kepingophyllum schellwieni • Psl. vemeuilis, £ Parasch mira Psl. moelleri Pseudo Sph. schwagerina • Monodixodina, Monodie- Sph. sphaerica sphaerica- Psf. Sphaeroschwagerina xodina Psl. firma firma Pseudo Sph.moelleri - schwagerina - Pseudo Sph £ Asselian Psf. fecunda Triticites, schwagerina Asselian moelleri- Psf. fecunda Ps. vulgaris - Triticites- Pseudoschwagerina range Zone P& fusitormis Psf. vulgaris• Schwagerina Psf. fusiformis

Orenburgian D. sokensis Orenburgian D. sokensis O Triticites T. jigulensis T. jigulensis Triticites Gzhelian T. siuckenbergi Gzhelian T. siuckenbergi Triticites ventricosus, T. ecutus - T. acutus • Triticites T. ardicus T. ardicus cullomenensis, Kasimovian Montiparus range Zone Kasimovian Triticites Montiparus Montiparus Irregularis montiparus montiparus

Fig. 6. Assemblage zones of the Permian representative fossils in South China and the international correlation (after Zhang, 1984). 16 Yasuhiro Ota

China Central Asia area The second session of of USSR The first session of Zhang(1984) stratigraphic conference stratigraphic conference

Dorashamian Palaeo- s>§ Palaeo- Palaeo- fusulina JC c fusulina .C c fusulina Palaeofusulina Ox OR

Dzhulfian Codono- Codono- Codono- fusiella fusiella fusiella Codonofusiella

Midiyan Yabeina Yabeina Yabeina Yabeina

Neo- Neo- Neo- Murgabian schwager- schwager- schwager- Neo- ina ina ina schwagerina Kubergandian Cancellina Cancellina Cancellina Cancellina

Bolorian Misellina Misellina Misellina Misellina Yakhtashian Pseudo o>2> Chalaro fusulina schwagerina

Sakmarian Pseudo Robusto schwager Robusto Robusto schwager schwager ina ina schwagerina ina Asselian Pseudo Sphaero schwager schwager "Schwagerina" ina ina Pseudo Orenburgian schwager Daixina Triticites Triticites & ina

Gzhelian Triticites Triticites Montiparus Kasimovian T.-Montiparus

Moscovian 03 C Fusulina Fusulina Fusulina £1 Fusulina

Fig. 7. Stratigraphic development of fusuhnaceans (after Zhang, 1984). Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 17

AKIYOSHI LIMESTONE GROUP

Y.OZAWA S. HANZAWA R. TORIYAMA (1923) (1941) (1953-1957)

subzone ll Yabeina sniraiwensis I? Sumatrina annae Yabeina Sumatrina Neoschwagarina Neoschwagerinaiperina| Verbeekina dowillei

ParafusuSna Verbeekina verbeeki c Pseudofusulina CO is ambigua Neoschwagarina craticulifera

CD Pseudofusulina Parafusulina japonica kaerimizensis Q_ Parafusulina Paraschwagerina Paralusulina Pseudofusulina lutugini <

Pseudoschwagerina Pseudofusulina ojomotosa Pseudoschwagerina vulgaris

Schwagerina SI Quasffusutina Pseudoschwagerina Triticites muongthensis Triticites simplex

c 2 "c Ctf Q = > Fusulinella Fusulinella' biconica CO bocki c c Lonsdaleia Profusulinelta CD £ (foriforms beppensis Q.

L NagatophyBum MillereOa sp. a satoi

Fig. 8. The fusulinacean zones of the Akiyoshi Limestone Group (after Toriyama, 1958). 18 Yasuhiro Ota he correlated the base of Pseudoschwagerina Zone (including Triticites simplex Sub- zone) with the base of Sakmarian in Russia, Wolfcampian in North America and Sakamotozawan in Japan (Fig. 8). Hasegawa (1958, 1963) divided the Akiyoshi limestone Group into eight zones. Of them, Profusulinella, Fusulina-Fusulinella and Yabeina-Lepidolina Zones were almost the same as those by Toriyama (1954a, b, 1958), but he subdivided Pseudoschwagerina Zone into an upper, the Pseudoschwagerina muongthensis Subzone and a lower, the Triticites simplex Subzone. At that time, he did not clearly indicate the Carbonifer ous-Permian boundary. However, he noticed the Mg-rich and oolitic limestones in the lower part of Pseudoschwagerina Zone. Murata (1961) divided the Akiyoshi Limestone Group into eight foraminiferal zones. He put the Carboniferous-Permian boundary below the base of the Pseudo schwagerina Zone, where the subfamily, Schwagerininae first appeared, and the genera, Fusulinella, Fusulina and Beedeina disappeared. M. Ota (1968, 1977) established 21 fossil zones (Table 4). He considered the Carboniferous-Permian boundary below the Triticites simplex Zone. Minato, Kato, Nakamura, Niikawa and Hasegawa (1984) gave a review on studies of the Carboniferous-Permian boundary in Japan and mentioned that the

Table 4. Biostratigraphic zones of the Akiyoshi Limestone Group (after M. Ota, 1977).

Geologic age Name ofthe fossil zone Symbol Thickness

Late Lepldollna multiseptata shlraiwensis Zone Puo +25m Colania douvillei Zone PmS 40m Verbeekina verbeekl Zone Pm y 20m Middle Neoschwagerina craticullfera Zone PmjS 25m C 15m CO Afghanellaschenckl Zone Pma2 E Parafusulina kaerimlzensis Zone Pma1 25m Misellina daudiae Zone PIS 20m Q_ Pseudofusulina ambigua Zone Ply 40m Early Pseudofusulina vulgaris Zone PI/5 50m Pseudoschwagerina (P.) muongthensis Zone Pla2 20m

Triticites simplex Zone Plal ±50m

Late Triticites (s. 1.) matsumotoi Zone Cua 20m

±30m CO Beedeina akiyoshiensis Zone Cmy Fusulinella biconica Zone Cm 3 -80m Middle 2 Akiyoshiella ozawalZone Cm a 3 20m

*^ Profusulinella beppensis Zone Cm a 2 20m 'c Pseudostaftella antiqua Zone 20m o Cma1 .a I— Millerellayowarensts Zone CIS 60m CO Nagatophyllum satol Zone 70m O Early Cly Zahrentoldes sp. Zone CI0 40m 80m Marginalia toriyama! Zone CI a Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 19

relationship between the Lower Permian and Carboniferous deposits in Japan is variable from place to place (Fig. 9). Ozawa and Kobayashi (1990) reexamined the fusulinacean zones of the Akiyoshi Limestone Group, and drew the Carboniferous-Permian boundary between the Daixina robusta-"Pseudoschwagerina" minatoi Zone and the "Sphaeroschwagerina" fusiformis Zone. Ozawa, Kobayashi and Watanabe (1990) established the new genus "Carbonoschwagerina" with Pseudoschwagerina morikawai Igo as the type species. They remarked that this genus represents Carboniferous age. They placed the Carbonif erous-Permian boundary at the same horizon as Ozawa and Kobayashi (1990). Watanabe (1991) emphasized the same opinion that the Carboniferous-Permian boundary should be placed under the Sphaeroschwagerina fusiformis Zone.

Fig. 9. Correlation of the Upper Carboniferous and the Lower Permian in Japan (after Minato et al., 1984).

Biostratigraphy of the Akiyoshi Limestone Group near the Carboniferous- Permian boundary in the three different areas

-1-1. Biostratigraphy of the Jigoku-dani area The first area investigated, Jigoku-dani, is located in the northwestern of the Akiyoshi Plateau(s. s.). This area topographically consists ofa deep valley with NE- 20 Yasuhiro Ota

SW trend, ranging from about 200 m to 350 m in altitude and well-developed karst topography. M. Ota (1977) confirmed the following fusulinacean zones in this area: Fusulinella biconica Zone, Triticites simplex Zone, Pseudofusulina vulgaris Zone and Pseudofusulina ambigua Zone. The Akiyoshi Limestone Group in this area is consid ered to have originally accumulated in a lagoonal sedimentary environment within the Akiyoshi organic reef complex and is geologically inverted in structure. How ever, in this area, fusulinacean zones such as the Beedeina akiyoshiensis Zone, Triticites (s. 1.) matsumotoi Zone, and Pseudoschwagerina muongthensis Zone of the generalized fusulinacean zones of the Akiyoshi Limestone Group (M. Ota, 1977) have not been confirmed yet and elements of the fusulinacean fauna have remained unknown. Topography of the Jigoku-dani area is characterized by the limestone lapie field and it is difficult to confirm the exact localities of the collected materials. Therefore, the author selected some traverses to measure with the name ofJI (JI Traverse 1-5) and collected materials along the traverses. Materials from localities 300 to 788 are mainly discussed here (Fig. 10). Limestones in the Jigoku-dani area are generally massive. They are white to gray white, but pardy dark brown in color. The dark brown color is considered to be caused by the secondary alteration, but the genesis needs to be carefully studied. The limestones in this area are ordinarily composed of micrite, with some intercalat ing limestone with sparry calcite cements. Frame building organisms of reef en vironment are almost absent. These features suggest that the limestones in the Jigoku-dani area were mostly accumulated under a low energy lagoon sedimentary environment. Based on the microscopic study of the collected specimens, 56 fusulinacean spe cies including two subspecies among 23 genera are discriminated (Table 5). Dis tribution of these fusuhnaceans and distinction of lithofacies are illustrated in Fig. 11. Distribution of the characteristic fusuhnaceans and the fusulinacean zones along five traverses, JI Traverse 1-5 are shown in Fig. 12. Furthermore, the detailed distribu tion of the fusulinacean species and the lithofacies along each traverse are shown in Figs. 13 and 14, respectively. From these examinations, nine zones including seven subzones were recognized in the Jigoku-dani area (Table 6). The representative fusuhnaceans of the proposed zones and the thickness of each zone measured along each traverse are shown in Table 7. From the distribution of these fusulinacean zones, it is confirmed that the Akiyoshi Limestone Group in this area has the general strike of N10°W, dipping to ward SW with angles of 10 to 20 degrees. Furthermore, the older fusulinacean zones are recognizable at higher topographical locations than the younger ones along the western slope of the valley, and therefore limestones in this area apparently exhibit an inverted succession. In addition, these limestones are mainly composed of micrite without the frame builders of organic reefs. They are considered to have accumu- •3

Fig. 10. The first investigated area, Jigoku-dani, showing survey traverses: JI Traverse 1-5 and their cardinal points. 22 Yasuhiro Ota

$ -I

££ Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 23

sm £33

lis Goo isiis me 24 Yasuhiro Ota

as,8 ill]

:££ £3333

B aSc

CO 85

g §3|3^ is a c

Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 25

JI Traverse 5

JI Traverse 3 1 JI Traverse 1 JI Traverse 4 110m Fig. 12. Distribution of the characteristic fusulinacean species (shown by the locality numbers) and the fusulinacean zones (1-9) along the JI Traverse 1-5. The following numbers are used for fusulinacean zones: 1. Fusulinella biconica Zone; 2. Fusulina cf. shikokuensis Zone; 3. Obsoletes obsoletus Zone; 4. Montiparus sp. A Zone; 5. Triticites yayamadakensis Zone; 6. Schwagerina (?) cf. satoi Zone; 7. Pseudoschwagerina muongthensis Zone; 8. Pseudofusulina vulgaris globosa Zone; 9. Pseudofusulina aff. ambigua Zone. The characteristic fusuhnaceans with localities are as follows: 332, Pseudoschwagerina muongthensis (Deprat); 387, Schwagerina (?) cf. satoi (Ozawa); 392, 439, 569, 605, Triticites yayamadakensis Kanmera; 454, 554, Montiparus (?) sp. A; 461, Fusulinella biconica (Hayasaka); 465, Fusulinella cf. obesa Sheng; 468, Protriticites toriyamai Ota; 477, 633, Obsoletes obsoletus (Schellwien); 489, 538, Protriticites matsumotoi (Kanmera); 517, Pseudofiisulinella hidaensis (Kanuma); 520, Protriticites masamichii Ota; 578, Schwagerina sp. A; 663, Montiparus sp. A; 686, Triticites yayamadakensis evectus Kanmera; 723, Pseudofusulina (?) sp. A; 729, Pseudoschwagerina sp.; 736, Paraschwagerina sp.; 766, Pseudofusulina aff. ambigua (Deprat). 26 Yasuhiro Ota

13. Distribution of the characteristic fusulinacean species (shown by the locality numbers) and the fusulinacean zones (1-9) along the JI Traverse 1-5. The following numbers are used for fusulinacean zones: 1. Fusulinella biconica Zone; 2. Fusulina cf. shikokuensis Zone; 3. Obsoletes obsoletus Zone; 4. Monti parus sp. A Zone; 5. Triticites yayamadakensis Zone; 6. Schwagerina (?) cf. satoi Zone; 7. Pseudoschwagerina Fig. 13-1. JI Traverse 1. muongthensis Zone; 8. Pseudofusulina vulgaris globosa Zone; 9. Pseudofusulinaa(T. ambigua Zone. &\p S4

•^1 *T1 d5' Obsakta obsoSctw \ ProtrWctXJ mMBumoal ftrcniffna cf* ih&oJttieaiit ProaiOcttajrtBltklll Protrttict tts tnxoustotot Momtpam (I) sp. A' IMtkfttscf.otai 7Wdc)»»fcJcfawij' TWtktet ct bona

7HUctei w»m«ftitfmto eveclm ScAmijeriai ip. A 7W(idKirazaJ4(

7WiJi4ies blcoojrax ' FksoUseiia ef. ' oka TMdcttes •&. dapla PtmtiiScixts MiyKBtl I Obsofeta obmlems mtkint ytymMctikmilj' THtfcftwcf. i»eraii QtfHifuja/ins sp. B

J 3*3 d5' 32 NJ U) en t3> Tf RraAaeBs ttccBir I FxudafmuIlBM (J) sp. A Asulloa cf. ibfibiioeiuff 7Wclcftcs cf. pje»rfrtt/ntplcx Ocaolna obmfcftii o AotfiJeftcs aacnmmtDi fteacfafcl»«m«ilia ip.' Qiustfuniibakfcs(7)ip.' fsnxf«r/n«i(trbia muanftbenllj Mostfparmsp.A* Amscfcw«faiai sp. THttcAmnarioi ftrtxfoAuuttu vcfeirti fjcboia' Qiasi&niflaa kmgbshnM fteuctoftnaUai afl. imAtf m Qjaiifiaulioj sp. A Acuda/uRtttn cf. vuCjirfs s.«. TWtfete»,wyinHicfafcnsft evectus TWUcite mJrW 28 Yasuhiro Ota

.irrestone Urrestone Lines;one Blackand jrrfistonc Lirestone Limestone BlackanT with with with dark with with with dark Locally rriaite rr.:r;.: sparry brown Subzone Zone Locally rriaite micritic sparry brown Subzone Zone matrix matrix calcrte color matrix matrix calate color cement limestone cerrent limestone 300

::•:•::•::• 5-3

304

•::•:•:•::•:•: 306

V-' 5-2 r/, "31? 4jl sir ice

m 316 317 7 4« 319

i® 21 :••:•:••: : 410 s 322 323 324 325 37-i

41/ —28~

'•::.•• 419 5-1 3X

422 534"

;.;....

311

313

318

436 360 •~~

y.i 440

:•:•:•:•••:•:•

445 1 446 6 :':•:•: 361 4 ~ss~

354

~356—

—370 457 3

461 375 376

375 Fig. 14-1. JI Traverse 1. Loc. 388 (upper "383 - -%:•- most of the left column) continues to Loc. 387 (lowermost of the right column).

Fig. !•!. Distribution of lithofacies along the JI Traverse 1-5. The following numbers arc used for fusulinacean zones: 1. Fusulinella biconica Zone, 2. Fusulina cf. shikokuensis Zone: 2-1. Fusulina cf. obesaSubzone, 2-2. Pseudofusulinella hidaensis Subzone, 3. Obsoletes obsoletus Zone: 3-1. Protriticites loriyamai Subzone, 3-2. Protriticites matsumotoi Subzone, 4. Montiparus sp. A Zone, 5. Triticites yayamadakensis Zone: 5-1. Triticites saurini Subzone, 5-2. Schwagerina sp. A Subzone, 5-3. Triticites biconkus Subzone, 6. Schwagerina (?) cf. satoi Zone, 7. Pseudoschwagerina muongthensis Zone, 8. Pseudofusulina vulgaris globosa Zone, 9. Pseudofusulina aff. ambigua Zone. Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group. Part I 29

L rrescne .. rrestc-e Limestone Black and Lirrestone Limestone Linesone Backano with with with dark with with with dark Locally rriaite rrtcritic sparry brown Subzone Zone Locally rriaite rriaitic sparry brown Subzone Zone matrix matrix catate color matrix matrix calate color cerrent Imestone cement Imestone

615

. 613 564 | wmm 553 5-3

561 4 560 :- "••«.••••—,,,,7,7,",',",",., 559 607

605 555 l 603

601 1

3-2 5 5-2

:•:•:•: :-

595 585

3-1 5/9 578 5// 576 •: ::••:•:• 5/5 • : ::-:-:::-:-: 57; :•:::. 5-1

570 559 2-2 Fig. 11-3. JI Traverse 3 (Loc. 569 to Loc. 616, right column). Loc. 568 (upper

2 most of the left column) continues to Loc. 2-1 569 (lowest of the right column).

1 Fig. 14-3. JI Traverse 3 (Loc. 509 to Loc. 568. left column).

Limestone Limestone Limestone Backand Lirrestone Lirrestone Lirrestone Biackand with with with dark with with with dark Locality rriaite micritic sparry brawn Subzone Zone Locally rriaite rriaitic sparry brown Subzone Zone matrrx matrix calate color matrrx matrix calate color cerrent irrestone cement rrestrjr.e

•:.-:•:-•.-:•-:•:

.:•:::•::

3 4/4 3 4/3 .. 4/2 4/1 483 4/0 2-2

2 •••: • 459 i 2 iX Fig. 14-2. JI Traverse 2 (Loc. 464 to Loc. 2-1 479, left column). 506 507 Fig. 14-2. JI Traverse 2 (Loc. 507 to Loc. •180, right column). 30 Yasuhiro Ota

jrreacne Limestone Limestone Biackand Lirrestone Lirrestone Limestone Bac.K ar,a with with with dark with with with dark Locally rriaite micrrtic sparry brown Subzone Zone Locality rriaite micritic sparry brown Subzone Zone matrix matrix caldte color matrix matiix calorie color cerrent limestone cerrent limestone «

", h; 7a

705 704 9

5 771

—

698 • •:•••:•-: "

•:•:-•:•:•:••:•. • " W

763

/60

685 684 •:.-3 756

690 679 678 8

669

-••:•:• •: •

™ 665 664 663 662 661 660 •: ::•:•:• • •:• 7 659 731 • ••:•.-.. .,• .. 657 .?••.-•••••••;, 655 ..:•:•: . 726 725 6

•:•:•::•.•:•:• .•

3 615 32 648 •:•:••:-:•:••:•:•••:••:•

643 .:•••:•.• 642 /14 611 616

638 Fig. 14—5. JI Traverse 5 (Loc. 713 to Loc. 63/ 788).

6a 3-1 :'.' 631 630 659

(27 22 2 £5

620 2-1 618 1

Fig. 11—1. JI Traverse 4 (Loc. 617 to Loc. 712). Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 31

Table 6. Fusulinacean zones in ascending order recognized in the Jigoku-dani area. Fusulinacean zones in the Jigoku-dani area 9. Pseudofusulina aff. ambigua Zone 8. Pseudofusulina vulgaris globosa Zone 7. Pseudoschwagerina muongthensis Zone 6. Schwagerina (?) cf. satori Zone 5. Triticites yayamadakensis Zone 5-3. Triticites biconicus Subzone 5-2. Schwagerina sp. A Subzone 5-1. Triticites saurini Subzone 4. Montiparus sp. A Zone

3. Obsoletes obsoletus Zone 3-2. Protriticites matsumotoi Subzone 3-1. Protriticites loriyamai Subzone

2. Fusulina cf. shikokuensis Zone 2-2. Pseudofusulinella hidaensis Subzone 2-1. Fusulinella cf. obesa Subzone

1. Fusulinella biconica Zone lated in a relatively low energy lagoon environment within the Akiyoshi organic reef complex. Distributions of fusulinacean zones are shown in Fig. 15 and the cross sections along A-A', B-B' and C-C, are respectively indicated in Fig. 16. The detailed characters of each fusulinacean zone are given as follows. 1. Fusulinella biconica Zone. The Fusulinella biconica Zone is the oldest in the Jigoku-dani area and is exposed in the highest part ofthe western slope of this area. The thickness is estimated to be about 2 m + . This zone is typified by the occurrence of Fusulinella biconica (Hayasa- ka). Limestones have a general NE strike and dip gently to northwest, but occa sionally dip toward the southeast. They are mainly composed of micritic limestones with intercalation of limestones with sparry calcite cements. 2. Fusulina cf. shikokuensis Zone The Fusulina cf. shikokuensis Zone conformably overlies the Fusulinella biconica Zone and is defined by the occurrence of Fusulina cf. shikokuensis Ishii. This zone is subdivided into two subzones, the lower, the Fusulinella cf. obesa Subzone and the upper, the Pseudofusulinella hidaensis Subzone. 2-1. Fusulinella cf. obesa Subzone. The Fusulinella cf. obesa Subzone is characterized by the occurrences of Fusulinella cf. obesa Sheng in association with Fusulinella cf. shikokuensis Ishii. Limestones of this Table 7. Representative fusuhnaceans in the proposed zones and the thickness of each zone measured along the surveyed traverses.

Representative fusuhnaceans ofeach zone in the Jigoku-dani area Thickness

9. Pseudofusulina aff. ambigua Zone Ji Route 1 Ji Route 3 JI Route 3 Ji Route 4 Ji Route 6 Pseudofusulina aff. amd&ua[766(16)], Psf. cf. vulgaris b.b.[766(6)]. 42+m, (766-788) 8. Pseudofusulina vulgaris globosa Zone 83m, Pseudofusulina vulgarisglobosa [738d>2, 755(l)-3, 763(2>-3], (736-766) Paraschwagerina spp.[786(2), 756(2), 756(8). 759(1)-1]. 7. Pseudoschuagerlna muongthensis Zone 17m, StaffeUamoelleri,Schubertettakingi, SchwagerinaokafuJiiT.S12o.-2], S. primigena[313f\, S. cf. prtncefw[312fj, 32+m, (729-736) 5. sp. A[3S2(2e>7], S. sp. B[S32D2], S. sp. C[311a, 317D],5. sp. D[382b-1], S. (7)aff. Au«fc«ft«wfa[S08c-l), (332-300) PseudoschwagerlnamuongthensisVlSUli-l, 332(la)-3], Ps. sp.[729(1)1. Ps. (7) sp.[800d-b]. 6. Schwagerina (?) of. satoi Zone 76m, 11m, Ozawainella off. magna, NankineUa sp. A Sehubertella lata, Triticites hayderuT379d], 7. michiae[379p], (387-332) (723-729) 7. cf. o6ai[S78d-2?], 7. cf. pseudosimplex[311 B.-2, 725(1)], 7. aff. stoyrf«:[379c-l], 7. aff. ai»uAii[37Sa-l], Schwagerina cf. «to&ais[836a-2,S86e, 336d], S. (?)cf. «atoi[387d2], "Pseudofusulina "cf. oacca[336b-3], 'Psf.' aff. /iwfbnni»[8791-2] Psf. (?) sp. A[360a, 387c-A 723], Rwosofu3ulinaarclicalS4Ba-l, 354a-2]. 5. Triticites yayamadakensis Zone 5-8. Triticites oiconlcus subzone 15m, Quasifusullna sp. B[890c-1, 614(1)],Triticites biconicw>[392b-l, 392b-2], 7. cf. iso«nji5[608d], (392-387) 32+m, 7. AuroJu>a*/uM392a-2], 7. yayamadakensis [392a-3. S92A-1. 605b-ll. (605-616) 5-2. Schwagerina sp. A snbxono 43m, Triticites biconicus,7. aff. simp/«x(586d], 7. su«u&f[581c-3], 7. yayamadakensislBSl}), (578-605) Schwagerina sp. A[578(6). 586b-2, 586i-l], 5. sp. B. 5-1. Triticites saurinl subzone 109m, 15m, Triticites cf. oonus[569k], 7. hidensisl421e.-l), 7. mfcAtae[694-(4)], 7. 8auniuT403a-3, 403b, 429a, 429b, (439-392) (569-578) 72m, 433a-l], 7. aff. simplex, T. yayamadakensis[489b, 569d], 7. yayamadakensis evectus [694(18), 569'(1), 686(1), (686-723) 687(b)-l]. 4. Montiparus sp. A Zone 34m, 20m, 24m, Quasifusulinalongissima[675(2), 675(4>2], Quasifusulina sp. A(675(3)], Montiparussp. A[663(l), 676(1), 679(1)], (454-439) (554-569) (663-686) M (?) sp. A[464a. 554(1)]. Triticiteshidensis. 7. cf. otai. 7. saurtro[673(8)l. 3. ObeoUtee obsoletus Zone 3-2. Protriticites matsumotoi subzone 31m, 14m, Obsoletes obsoletus[469a7, 637(b)], Protriticites matsumotoli4S9c, 538a, 634(1)], Pwt yano£Wai[540a], (538-554) (634-663) Quasifusulinoides (?) sp. [639(1)1. 3-1. Profrtficltee toriyamal subzone 9m, 63m, lm, Obsoletes obsoletus[4Tla, 532a. 633-1], Protriticites masamichUlBWa), Prot loriyamai [468c]. (454-477) (520-538) (633-634) 2. Fusulina of. shikokuensis Zone 2-2. Pseudofusulinella hidaensis subzone 2m, Pseudofusulinella fcdae/w»[492(2)-2, 517a. 517b], Fusulina ct.shikokuensis[492&-l, 492b]. (517-520) 2-1. Fusulinella of. ofreso subzone 8m, Fusulina ct. shikokuensts[62U2)], (465-468) Fusulinella cf. ©4e*a[465a, 467a]. 2m 44+m, (481-477) (489-507) 2. Fusulinella biconica Zone 2+m, Fusulinella biconica[461a, 618a-l]. (462-461) n

Fig. 15. Distribution of fusulinacean zones in theJigoku-dani area. Thefollowingnumbersare usedfor fusulinaceanzones:1. FusulinellabiconicaZone;2. Fusulinacf. shikokuensis Zone;3. ObsoletesobsoletusZone: 1.Montiparussp. A Zone;5. TriticitesyayamadakensisZone;6. Schwagerina(?) cf. MtoiZone; 7. PseudoschwagerinamuongthensisZone; 8. PseudofusulinavulgarisglobosaZone; 9. Pseudofusulinaaff. ambigua Zone. 34 Yasuhiro Ota

350m 5. Triticites yayamadakensis Zone 6. Schwagerina (?) cf. saroi Zone 7. Pseudoschwagerina muongthensis Zone 300m 8. Pseudofusulina vulgaris globosa Zone

9. Pseudofusulina 250m . aff. ambigua Zone

200m A 1:1

1. Fusulinella biconica Zone 2. Fusulina cf. shikokuensis Zone J v' 3. Obsoletes obsoletus Zone 350m Montiparus sp. A Zone

£- S. Triticites yayamadakensis Zone 300m

6. Schwagerina (?) 250m. t cf. satoi Zone 7. Pseudoschwagerina 200m' / muongthensis Zone B 1:1 a-

2. Fusulina cf. shikokuensis Zone 350m ^ 3. Obsoletes obsoletus Zone

300m .4. Montiparus sp. A Zone

^ 5. Triticites yayamadakensis Zone

250m

200m C iiic

Fig. 16. Cross sections along A-A', B-B' and C-C in the Jigoku-dani area. Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 35 subzone strike N10°W, gently dipping toward southwest. They are composed of micritic constituents, but limestones with sparry calcite cements are intercalated at the basal partofthis subzone. Additionally, limestones ofblack todark brown color occur in this basal horizon, though the origin of the black to dark brown limestones has not been determined. 2-2. Pseudofusulinella hidaensis Subzone. The base of the Pseudofusulinella hidaensis Subzone is marked by the first occur rence of Pseudofusulinella hidaensis (Kanuma) and this diagnostic species is associated with Fusulina cf. shikokuensis Ishii. Limestones of this subzone are estimated to be 2 m in thickness, and have a general NW strike and gentle dip toward the southwest. They are characterized by micrite, but are partly intercalated by limestones with the sparry calcite cements. 3. Obsoletes obsoletus Zone. The diagnostic species of the Obsoletes obsoletus Zone is Obsoletes obsoletus (Schell- wien). In theJigoku-dani area, this zone is recognized as an interval from the hori zon with the first occurrence of the genus Obsoletes or the genus Protriticites, to the horizon with Montiparus (?) sp. A or Montiparus sp. A. It is subdivided into two subzones, the lower, the Protriticites toriyamai Subzone with primitive species of Protriticites, and the upper, the Protriticites matsumotoi Subzone characterized by Protriticites matsu motoi (Kanmera). 3-1. Protriticites toriyamai Subzone. In this subzone, primitive species of Protriticites, such as Protriticites toriyamai Ota and Protriticites masamichii Ota, are associated with the diagnostic species, Obsoletes obsoletus (Schellwien). These primitive species of Protriticites are very important to determine the upper limit of the Middle Carboniferous. This subzone was named after the characteristic occurrences of Protriticites toriyamai Ota. Maximum thickness of this zone is estimated as 63 m. Limestones of this zone have a wide variety of matrices from micrites to sparry calcites though they are somewhat coarser in grain size. Black to dark brown limestones previously mentioned are observed in this

zone. 3-2. Protriticites matsumotoi Subzone. The Protriticites matsumotoi Subzone is defined by the first occurrence of Protriticites matsumotoi (Kanmera). The other constituent species of this subzone are Obsoletes obsoletus (Schellwien), Protriticites yanagidai Ota and Quasifusulinoides (?) sp. This zone has an estimated maximum thickness of about 31 m. Limestones of this subzone strike NW and have a gentle dip toward the southwest. This zone is mostly limestones with micrite matrix, but those with sparry calcite cements are intercalated in the lower part of this subzone. The grains of sparry calcite cements are rather coarse in size. Black to dark brown limestones are common in this zone. 4. Montiparus sp. A Zone. The Montiparus sp. A Zone is characterized by the occurrence of Montiparus sp. A. 36 Yasuhiro Ota

However, limestones along some traverses, did not yield Montiparus sp. A, but were characterized by Montiparus (?) sp. A. Montiparus (?) sp. A is closely similar to Montiparus sp. A, except for some features. Limestones of this zone are estimated to be about 34 m in maximum thickness. They generally show a NW strike, dipping toward southwest direction, with an occasional NE strike, dipping toward northwest direction. The main constituent of limestones is micrite. Black to dark brown limestones are also present in this zone. The following fusuhnaceans also occur in this zone: Quasifusulina longissima (Moller), Quasifusulina sp. A, Triticites hidensis Igo, Triticites cf. obai Toriyama, and Triticites saurini Igo. 5. Triticitesyayamadakensis Zone. The Triticites yayamadakensis Zone is defined by the occurrence of Triticites yayamadakensis Kanmera. In the Jigoku-dani area, Triticites yayamadakensis Kanmera is easily recognized, and is a good index fossil. The estimated thickness of this zone is 124m. This zone is subdivided into the following three subzones by characteristic fusuhnaceans in ascending order. 5-1. Triticites saurini Subzone. This subzone is characterized by abundance of Triticites saurini Igo. The base of this zone is demarcated by the first occurrence of Triticitesyayamadakensis Kanmera or Triticites yayamadakensis evectus Kanmera. The following fusuhnaceans are also in association with Triticites cf. bonus Chen and Wang, T. hidensis Igo, T. michiae Toriyama, T. aff. simplex (Schellwien). Triticites yayamadakensis evectus was first described by Kanmera (1958) from the Yayamadake Limestone, Kyushu, Japan. He pointed out the difference of the stratigraphic horizon between Triticites yayamadakensis yayamadakensis Kanmera and Triticites yayamadakensis evectus Kanmera. However, the difference was not confirmed in the Jigoku-dani area. The thickness of this subzone attains 15 m at most. Lime stones of this subzone show general strike of about N14°W and dip about 18° toward SW. Limestones are mainly composed of micritic matrices, and black to dark brown limestones are intercalated in some horizons. 5-2. Schwagerina sp. A Subzone. The Schwagerina sp. A Subzone is characterized by the occurrence of Schwagerina sp. A and Triticitesyayamadakensis Kanmera. The lowest boundary of this subzone is demarcated by the first occurrence of the genus Schwagerina. The occurrence of Schwagerina sp. A was also ascertained from the AK Traverse in front of the Akiyoshi- dai Museum of Natural History and this species possibly has a wide distribution in the Akiyoshi Limestone Group. The general strike and dip of limestones in this subzone are unknown. However, from the conformable relationship with the underlying limestones, they are common to those of the underlying subzone. Furthermore, the limestone sequence of this subzone intercalates limestones with sparry calcite cements as were seen in the underlying Triticites saurini Subzone. Limestones of this subzone yield the following fusuhnaceans such as Triticites biconicus Toriyama, Triticites aff. Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 37 simplex (Schellwien), Triticites suzukii (Ozawa), and Schwagerina sp. B. 5-3. Triticites biconicus Subzone. The Triticites biconicus Subzone is characterized by the abundant occurrences of Triticitesyayamadakensis Kanmera and the characteristicoccurrence of Triticites biconicus Toriyama. Therefore, the fusulinacean constituents of this subzone clearly distin guish them from those of other subzones. Triticitesyayamadakensis Kanmera from this subzone has a rather advanced form, such as larger shell and thicker spirotheca, than those in the lower horizon. Limestones of this subzone have a general strike of about N10°W and gently dip to the south ward. The basal part of this subzone mainly consists of limestones with sparry calcite cements. Matrices of limestones gradually change from sparry calcites to micrites upward in the section. However, the uppermost part of this subzone contains coarse grains of fossil fragments of frame builders. In the Jigoku-dani area, this zone is the upper limit of distribution of black to dark brown limestones. The following fusuhnaceans are recognized in this subzone: Quasifusulina sp. B, Triticites cf. isaensis Toriyama and Triticites kuroiwaensis Toriyama. 6-1. Schwagerina (?) cf. satoi Zone. The lowest part of the Schwagerina (?) cf. satoi Zone is defined by the horizon from the first occurrence of Schwagerina (?) cf. satoi (Ozawa) or Pseudofusulina (?) sp. A to the first occurrence of Pseudoschwagerina muongthensis (Deprat) or Pseudoschwagerina sp. The estimated thickness of this zone is 76 m. The following fusuhnaceans are also recognized in this zone: Ozawainella aff. magna Sheng, Nankinella sp. A, Schubertella lata Lee and Chen, Triticites haydeni (Ozawa), T. michiae Toriyama, T cf. obai Toriyama, T. cf. pseudosimplex Chen, T. aff. simplex (Schellwien), T. aff. suzukii (Ozawa), Schwagerina cf. stabilis (Rauser), "Pseudofusulina" cf. bacca Morikawa and Isomi, "Psf" aff.fusiformis (Schellwien), and Rugosofusulina arctica (Schellwien). The fusulinacean index fossil, Schwagerina (?) cf. satoi (Ozawa) resembles the specimen that was first described as Schellwienia satoi by Ozawa (1925). As it has been already pointed out by Ozawa (1925) and Toriyama (1958), Schwagerina satoi (Ozawa) is intermediate in form between Schwagerina and Pseudoschwagerina. Schwagerina (?) cf. satoi (Ozawa) from the Jigoku-dani area also has an intermediate form between Schwagerina and Pseudoschwagerina morikawai Igo and the present form is similar to the microspheric form of Pseudoschwagerina. The question whether the present species is referable to the inflated schwagerinids is uncertain. This species, however, is very important for regional correlation. Fusuhnaceans of this zone are distinguished from those of the underlying zone by their rather advanced forms in having larger shell, and thicker spirotheca. Weakly developed phrenothecae occur in some specimens. The phrenothecae are generally observed in Pseudofusulina, but the present specimens are found in a lower horizon than the horizon of Pseudofusulina as known before in the Akiyoshi Limestone Group. More detailed studies are required to solve the problem of the "Pseudofusulina" Horizon. 38 Yasuhiro Ota

Limestones of this zone are mainly composed of micritic matrices. However, the upper part of the underlying zone contains some fragments offossils of reef frame builders. No evidence of change in lithofacies of the lower Triticites biconicus Subzone to the lower part of the Schwagerina (?) cf. satoi Zone suggest a remarkable hiatus. 7. Pseudoschwagerina muongthensis Zone. The lowest part of the Pseudoschwagerina muongthensis Zone in the Jigoku-dani area is marked by the first occurrence of the genus Pseudoschwagerina, namely, Pseudo schwagerina muongthensis (Deprat) or Pseudoschwagerina sp. In the Jigoku-dani area, well preserved specimens of Pseudoschwagerina were not obtained. Along the AK Traverse near the Akiyoshi-dai Museum of Natural History, microspheric forms of Pseudoschwagerina are obtained from a stratigraphically slightly lower position com pared with that of the megalospheric forms. Along the northern JI Traverse, JI Traverse 5, the microspheric form of Pseudoschwagerina also occurs in a lower horizon about 2 m below the megalospheric form. However, along the other JI Traverses, the microspheric form has not yet been confirmed. Therefore, the boundary on the underlying zone is tentatively drawn between the horizons of microspheric form of Pseudoschwagerina sp. and megalospheric form of Pseudoschwagerina muongthensis (De prat). The estimated maximum thickness of this zone is 32 m-K Limestones in the lower part of this zone, consist of rather coarse constituents and intraclasts. The upper part of the underlying Schwagerina (?) cf. satoi Zone is dominated by micritic limestones. The changes of lithofacies is present between the upper part of Schwagerina (?) satoi Zone and the lowest part of the Pseudoschwagerina muongthensis Zone. However, each zone is conformably distributed with nearly the same strike and dip. Therefore, a visible gap is not assumed between the two zones in the field. On the other hand, limestones gradually become micritic in texture as the stratigra phy is studied from the lower to the upper part in the present zone. This means that the energy of the environment decreased. The recognized species of this zone are as follows: Staffella moelleri Ozawa, Schubertella kingi Dunbar, Schwagerina okafujii Toriyama, Schwagerina primigena Nogami, Schwagerina cf. princeps (Ehrenberg), Schwagerina sp. A, Schwagerina sp. B, Schwagerina sp. C, Schwagerina sp. D, Schwagerina (?) aff. kueichihensis (Chen), Pseudofusulina regularis (Schellwien) and Pseudoschwagerina (?) sp. 8. Pseudofusulina vulgaris globosa Zone. The Pseudofusulina vulgaris globosa Zone is characterized by the abundant occur rence of Pseudofusulina vulgaris globosa (Schellwien) and the association of Para- schwagerina sp. In this zone the author could not directly determine the strike and dip of the limestone. The present zone is considered to conformably overlie the Pseudoschwagerina muongthensis Zone. Limestones in this zone are estimated to be at most 83 m in thickness. They are characterized by micritic texture. However, the lowest part of this zone is composed of sparry calcite cements with rather coarse grains. The grain size of limestones near the top of the Pseudoschwagerina muongthensis Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 39

Zone is micritic. The changes of lithofacies are present between the top of the Pseudoschwagerina muongthensis Zone and the lowest part of this zone. 9-1. Pseudofusulina aff. ambigua Zone. The Pseudofusulina aff. ambigua Zone is the youngest zone, characterized by the occurrence of Pseudofusulina aff. ambigua (Deprat). The index fossil, Pseudofusulina aff. ambigua (Deprat), is closely similar to Fusulina ambigua of Deprat (1913), and Pseudofusulina ambigua by Toriyama (1958). However, the present species differs from the above species in having a larger proloculus. More specimens are necessary to determine the specific position. Distribution of this zone is restricted near the bottom ofJigoku-dani along the northern slope. The estimated thickness is 42 m at least. This zone is characterized by rather coarse limestones. Near the boundary between the underlying zone and the present one, the limestones with sparry calcite cements intercalate with somewhat coarse grained varieties. The limestones gradu ally decrease in grain size from the lower to the upper, and they become micritic in texture. However, they change to limestones with sparry calcite cements near the top of this zone.

-1-2. Correlation The Carboniferous and Permian chronostratigraphic units have been examined in Japan for a long time and the Middle Carboniferous and Lower Permian biostratigraphic units and their boundaries are currently being debated around the world. In the Akiyoshi region, the Akiyoshi Limestone Group has been studied since Ozawa (1923) and many important studies of Japanese Carboniferous and Permian geology were carried out there, for example, the establishment of the fusulinacean specific zones of the Akiyoshi Limestone Group (Toriyama, 1958), the paleoenvironmental investigation of the Akiyoshi Limestone Group as an organic reef complex (M. Ota, 1968), the examination on the geologic history of the lowest to lower part of the Akiyoshi Limestone Group in the northeastern part of the Akiyoshi Plateau (Yanagida, et al. 1971), and the establishment of the local standard of the biostratigraphic units in the Akiyoshi Limestone Group (M. Ota, 1977). Recently, the Middle Carboniferous and Lower Permian biostratigraphic units were actively discussed and some important results were reported, namely, by Hasegawa (1988), Ueno (1989), Ozawa and Kobayashi (1990), Ishii (1990), Watanabe (1991) and Y. Ota and M. Ota (1993). The refinement of the fusulinacean zones will contribute not only for making clear the stratigraphic transition of fusuhnaceans, but also for establishing the phylogeny of fusuhnaceans. In addition, the regional examination of the chronostratigraphic units with sedimentological analysis requires careful at tention. In the investigated area, nine fusulinacean zones including seven subzones were discriminated. The older limestones are successively exposed in topographically higher positions along the slope ofJigoku-dani without any remarkable hiatus. The Jigoku-dani area AKarea M. Ota (1977) Hasegawa (1988) Ueno (1989) Ozawa and Kobayashi Ishii (1990) Watanabe (1991) Ota and Ota (1990) Pseudofusulina PsTambtgua] aff. ambigua Z. Rob, schellwieni z. Pseudofusulina Psf. vulgaris Z. Psf. vulgaris Z. Psf. vulgaris aubz. Psf. ex. gr. vulgaris z. Psf. vulgaris Z. Chalaroschwagerina Rob. vulgaris globosa Z. vulgaris z. schellwieni schellwieni • Psf. vulgaris vulgaris Z. Rob. scheUwieni pamirica • S. krotowi Z. Dutkevttchia Parasch. spUndidaZ akiyoshiensis Z. Pseudoschwagerina Ps muongthensis Z. 75 Pseudoschwagerina Z. Alp. (?) fusiformis z. Ps. n. «p. Z. '*. muongthensison£tA< z. 5. globulusjaponials muongthensis Z. IPs.) muongthensis Z. Ps. miharanoensis Z. Ps miharanoensis Z. Alp. saigusai • Ps. cf. robusta Z. Ps. muongthensis Z. Sph. pavlooi Ps muongthensis Z. 'Sph." fusiformis Z. Sph. fusiformis z. Sph. fusiformis Z.

Schwagerina (?) T. simplex Z. T. simplex Z. T. simplex subz. T. simple Dx. cf. robusta • T. hidensis z. "Ps." minatoi Z. cf. satoi Z. "Ps" minatoi Z. "Ps * morikawai Z. TT< S .msatoiZ. Yj. " morikawai Z. Triticites S. tp. A Z. T.(R.)stuckenbergiZ. yayamadakensis Z. T. (JR.) paraarctieus Z. T.exsculptusZ. T. exsculptusz. T.yayamadakensis~Z~ T.yayamadakcnsis~ M. Montiparus sp. A Z. M. sp. A Z. M. matsumotoi Z. matsumotoi inflatus Z. M. montiparus - Qfd. ohtanii Z. Obsoletes obsoletus Z~. T. matsumotoi subz. iVot Ob. oo3oieiu«Z. Qfdsx,.AZ. T. (s. 1.) matsumotoi Z. 'At toriyamai z. (Prot) matsumotoi z. Prot. matsumotoi Z. «!•ot sp. z. Trot subschwagerinoides Z. Ob. obsoletus Z. Fusulina, Psflla. hidaensis Z. Beedeina P^Ua hidaensis Z. P. kuriltiensis z. ef. shikokuensis Z. fl. akiyoshiensis Z. akiyoshiensis z. fffa. paemtoooefct Z. ,F. ohtanii z. fl. akiyoshiensis Z. * B. higoensis z. Psflla. UoiZ. PsfUaT

Fusulinella biconica Z. Fusulinella biconica Z. FUa. taishakuensis~ FUa. biconicaZ. Fusulinella biconica Z. FUa. biconica z. FUa. simplicata z.

Fig. 17. Correlation among the Middle Carboniferous to Early Permian biostratigraphic units established in the different areas of the Akiyoshi Limestone Group and relevant sections. Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 41

following fusulinacean zones are successively discriminated from the top to the bottom along the slope: 1. Fusulinella biconica Zone, 2. Fusulina cf. shikokuensis Zone: Fusulinella cf. obesa Subzone, Pseudofusulinella hidaensis Subzone, 3. Obsoletes obsoletus Zone: Protriticites toriyamai Subzone, Protriticites matsumotoi Subzone, 4. Montiparus sp. A Zone, 5. Triticites yayamadakensis Zone: Triticites saurini Subzone, Schwagerina sp. A Subzone, Triticites biconicus Subzone, 6. Schwagerina (?) cf. satoi Zone, 7. Pseudoschwager ina muongthensis Zone, 8. Pseudofusulina vulgaris globosa Zone, and 9. Pseudofusulina aff. ambigua Zone. In this chapter, the author presents a correlation chart (Fig. 17) of each zone in the Jigoku-dani area with Middle Carboniferous to Early Permian biostratigraphic units established by workers in different areas of the Akiyoshi Limestone Group. 1. Fusulinella biconica Zone. The Fusulinella biconica Zone was characterized by the occurrence of Fusulinella biconica (Hayasaka). This zone was first introduced by Toriyama (1954a) with chronostratigraphic position of the Akiyoshian Series for this zone. According to M. Ota (1977), the lower part of Fusulinella biconica Zone is characterized by rather primitive species of Fusulinella, namely, Fusulinella simplicata Toriyama. Fusulinella biconica (Hayasaka) typified the middle part of the zone and Fusulinella itoi Ozawa, the upper part. Ueno (1989) divided the Fusulinella Zone into the following two zones, the lower, the Fusulinella biconica Zone and the upper, the Fusulinella taishakuensis Zone. In Jigoku-dani, the Fusulinella biconica Zone is definitively located at the top of the slope of the Jigoku-dani area, but the Fusulinella taishakuensis Zone was not con firmed in this area. This zone corresponds to Fusulinella Zone in other areas. 2. The Fusulina cf. shikokuensis Zone is characterized by the first occurrence of subfamily Fusulininae, especially by Fusulina cf. shikokuensis Ishii. This zone is divided into two subzones, the lower, the Fusulinella cf. obesa Sub- zone, and the upper, the Pseudofusulina hidaensis Subzone. The Fusulinella cf. obesa Subzone, is characterized by Fusulinella cf. obesa Sheng. This subzone probably corresponds to the Kurikian Series that was proposed by Kanmera (1952) from the fusulinacean biostratigraphy of the Yayamadake Limestone in the outer zone of Kyushu. Furthermore, this subzone is stratigraphically correlative with the Beedeina akiyoshiensis Zone by M. Ota (1977). According to him, the Beedeina akiyoshiensis Zone is typically developed in the Shishide-dai area, the northeastern part of Akiyoshi-dai with distinguishable litho- and biofacies from the subjacent zone. In Jigoku-dani, limestones of this subzone do not contain reef building organisms and are considered to have accumulated in a lagoonal environment within the Akiyoshi organic reef complex. Beedeina akiyoshiensis (Toriyama) has not been found yet. The difference of the fusulinacean assemblage seems to be dependent on the dif ference of the bio- and lithofacies of limestones. This subzone is correlated to the Fusulina Zone elsewhere. The upper subzone, the Pseudofusulinella hidaensis Subzone, is characterized by the 42 Yasuhiro Ota occurrence of Pseudofusulinella hidaensis (Kanuma). This zone was first introduced by Ozawa and Kobayashi (1990) in the Akiyoshi Limestone Group. However, at present, the occurrence of this species is confined to particular areas. In the Jigoku- dani area, Pseudofusulinella hidaensis (Kanuma) is found in some localities, but its distribution could not be traced widely. This subzone is probably correlated with the upper part of the upper Fusulina-Fusulinella Zone. 3. Obsoletes obsoletus Zone The Obsoletes obsoletus Zone is defined by the occurrence of Obsoletes obsoletus (Schellwien). This zone is subdivided into two subzones, the lower Protriticites toriyamai Subzone and the upper Protriticites matsumotoi Subzone. The lower, Protriticites toriyamai Subzone comprises primitive species of Protriti cites, namely Protriticites toriyamai Ota and Protriticites masamichii Ota. This subzone seems to be also characterized by the first appearance of very finely perforated walls in genus. Distribution of this subzone is restricted in its stratigraphic distribution. The Protriticites toriyamai Subzone is considered to be the basal zone of the Hikawan that was first introduced at Hikawa Valley, Kyushu, by Kanmera (1952). Addi tionally, this subzone is equivalent to the lower part of Obsoletes-Protriticites Zone or Obsoletes Zone in other areas. The upper, Protriticites matsumotoi Subzone is characterized by the occurrence of Protriticites matsumotoi (Kanmera) with Obsoletes obsoletus (Schellwien). The basal boundary of the Protriticites matsumotoi Subzone with the underlying Protriticites tori yamai Subzone is marked by the first occurrence of Protriticites matsumotoi (Kanmera). Protriticites matsumotoi (Kanmera) was first described by Kanmera (1955) under the generic name of Triticites (s. 1.) and this species is a diagnostic one of the Hikawan. Here, the author treats this species as the genus Protriticites by its having the "Protriticites-tyot wall" only in the outer volution. This subzone may be equivalent to a lower part of Hikawan and the upper part of the Obsoletes-Protriticites Zone, and can be correlated with the Triticites (s. 1.) matsumotoi Zone by M. Ota (1977). In the AK area and some other regions, the occurrence of the genus Quasifusulinoides was reported from the upper part ofProtriticites Zone and/or the overlying strata. In the Jigoku-dani area, however, the upper part of the present subzone yields Quasifusuli noides (?) sp., but no well-preserved specimen of Quasifusulinoides were obtained. The upper part ofthis zone is possibly correlative with the Quasifusulinoides Zone in other

areas. 4. Montiparus sp. A Zone. The Montiparus sp. A Zone is characterized by the occurrence of the genus Montiparus, and the basal boundary of this zone is drawn by the first occurrence of Montiparus sp. A or Montiparus (?) sp. A. The upper limit of this zone is defined by the first occurrence of Triticites yayamadakensis Kanmera and T.yayamadakensis evectus Kanmera. The genus Montiparus was first introduced by Rozovskaya (1948) as a subgenus of Triticites (s. 1.) with the name of Triticites montiparus Ehr. em. Moell. Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 43

Davydov (1990) showed the phylogenetic line of Protriticites-Montiparus-Rauserites. In the Jigoku-dani area, continuation of the limestone sequence is confirmed without any remarkable hiatus from the Protriticites matsumotoi Subzone to the Montiparus sp. A Zone. This generic transition from the genus Protriticites to the genus Montiparus in the above phylogenetic line is acceptable in the Jigoku-dani area. Therefore it is possible to establish the datum level by the first occurrence of the genus Montiparus. This zone probably corresponds to the Montiparus Zone or the lower part of Triticites (s. 1.) Zone. 5. Triticites yayamadakensis Zone. The Triticites yayamadakensis Zone is characterized by the occurrence of Triticites yayamadakensis Kanmera. This zone is subdivided into three subzones, the lower, the Triticites saurian Subzone, the middle, the Schwagerina sp. A, and the upper, the Triticites biconicus Subzone. The diagnostic species of this zone, Triticites yayama dakensis Kanmera was described from the Yayamadake Limestone (Kanmera, 1955). Therefore, the Triticitesyayamadakensis Zone in the Jigoku-dani area is correlated to the Triticites yayamadakensis Zone of the upper Hikawan Series (Kanmera, 1952; Tori yama 1967). The representative species of the lower, the Triticites saurini Subzone, is Triticites saurini Igo first reported from Fukuji, Hida Massif, central Japan (Igo, 1957). This species has a shell of large size with highly complicated septa and well-developed chomata. In the Jigoku-dani area, this species is associated with Triticites yayama dakensis evectus Kanmera that was originally reported from a horizon higher than that of Triticites yayamadakensis yayamadakensis Kanmera. Therefore, a slight doubt on the stratigraphic position of this subzone still remains. More detailed examinations of the fusulinacean constituents of this subzone are necessary to confirm the exact stratigraphic position. The middle part of this zone, the Schwagerina sp. A Subzone, is characterized by the abundant occurrence of Schwagerina sp. A. Outside the Jigoku-dani area, this subzone is also confirmed along the AK Traverse. The boundary with the lower subzone is defined by the first occurrence of the genus Schwagerina. Therefore, the basal boundary of this subzone possibly coincides with lower to middle part of the Triticites-Schwagerina Zone(s. s.). The upper subzone, the Triticites biconicus Subzone, is discriminated by predomi nance of Triticites biconicus Toriyama. In theJigoku-dani area, the present subzone is distributed over the Schwagerina sp. A Subzone. This subzone also contains Triti cites yayamadakensis Kanmera in association with Triticites biconicus Toriyama. Triti cites yayamadakensis from this subzone is very similar to Triticites ozawai originally described by Toriyama (1958) and Schellwienia montipara (Ehrenberg) by Ozawa (1925), respectively from the Akiyoshi Limestone Group. Triticites yayamadakensis from this subzone has an intermediate form between the above two species. On the other hand, Triticites ozawai Toriyama was reported from the Triticites simplex Zone in 44 Yasuhiro Ota the Akiyoshi Limestone Group (M. Ota, 1977). Summarizing these evidences, the Triticites biconicus Subzone possibly corresponds to the upper part of the Triticites simplex Zone(M. Ota, 1977). These three subzones, are correlative with the middle and upper part of the Triticites simplex Zone (M. Ota, 1977). 6. Schwagerina (?) cf. satoi Zone. The lower boundary of the Schwagerina (?) cf. satoi Zone is tentatively drawn by the first occurrence of Schwagerina (?) cf. satoi (Ozawa) and Pseudofusulina (?) sp. A. The distinguishing species, Schwagerina (?) cf. satoi (Ozawa) from the Jigoku-dani area has an intermediate form between the inflated schwagerinids, e.g. Pseudo schwagerina, and not inflated ones, and this species is very important for correlation. This zone also contains the following fusuhnaceans: Ozawainella aff. magna Sheng, Nankinella sp. A, Schubertella lata Lee and Chen, Triticites haydeni (Ozawa), Triticites michiae Toriyama, Triticites cf. obai Toriyama, Triticites cf. pseudosimplex Chen, Triticites aff. simplex (Schellwien), Triticites aff. suzukii (Ozawa), Schwagerina cf. stabilis (Rauser), "Pseudofusulina" cf. bacca Morikawa and Isomi, "Pseudofusulina" aff. fusi formis (Schellwien) and Rugosofusulina arctica (Schellwien). In comparison with fusuhnaceans of the underlying zone, those of this zone are characterized by having advanced forms, such as larger shell and thicker spirotheca. It is apparent that fusulinacean diversity rapidly increased in the Schwagerina (?) cf. satoi Zone. In addition, coarse grained limestones with fragments of reef frame builders are inter calated near the boundary between the present zone and the underlying zone. The changes of lithofacies and faunas are present near the basal boundary of the present zone. On the other hand, this zone is also characterized by the appearance of these fusuhnaceans that possess the phrenothecae typically recognized in the genus Pseudofusulina. Degree of the development is weak, but the phrenothecae can be observed in some specimens. Summarizing these facts, the author tentatively correlates the basal boundary of the Schwagerina (?) cf. satoi Zone with the appearance of "Pseudofusulina" or the basal boundary of the Daixina Zone. 7. Pseudoschwagerina muongthensis Zone. The Pseudoschwagerina muongthensis Zone is demarcated from the underlying zone by the first occurrence of the genus Pseudoschwagerina. This lower boundary possibly coincides with the first occurrence of the inflated schwagerinids. However, Schwager ina (?) cf. satoi (Ozawa) in the underlying zone has the intermediate form between Schwagerina and Pseudoschwagerina. Therefore, the basal boundary of this zone is drawn by using fusuhnaceans with typically inflated shell. In the Jigoku-dani area, they are represented by Pseudoschwagerina muongthensis (Deprat) and Pseudoschwagerina sp. Unfortunately, well-preserved materials of Pseudoschwagerina have not been obtained from the Jigoku-dani area, and as a result the detailed stratigraphic dis cussion of this zone is very hard to make clear. However, an obtained sagittal section of the microspheric form of Pseudoschwagerina sp. is closely similar to that of Pseudoschwagerina morikawai Igo from the AK area in front of the Akiyoshi-dai Muse- Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 45

um. Outside the microspheric form of Pseudoschwagerina, the megalospheric form of Pseudoschwagerina muongthensis (Deprat) was obtained from a slightly higher horizon than that of the former along the JI Traverse 5. This stratigraphic relationship, however, was not confirmed in other traverses. This zone can be correlated with the strata containing Pseudoschwagerina and typical inflated schwagerinids. Besides, limestones near the lowest boundary of this zone are composed of rather coarse limestones with sparry calcite cements. Conspicuous changes of lithofacies from the top of the Schwagerina (?) cf. satoi Zone to the basal part of the Pseudoschwagerina muongthensis Zone are apparently observed as stated previously. The facies change seems to be closely related to the appearance of the genus Pseudoschwagerina. From the above facts, the first occurrence of the genus Pseudoschwagerina becomes an excellent marker for the correlation of the basal part of the Lower Permian. In Japan, the Lower Permian is represented by the Sakamotozawan Series in Sakamoto- zawa and Nagaiwa areas, with the Kitakami massif as the type locality. Toriyama (1963) proposed two subzones for the Sakamotozawan, namely the lower Pseudo schwagerina morikawai Subzone and the upper Pseudofusulina vulgaris Subzone. Accord ing to Kanmera and Mikami (1965a, b), the basal part of the Sakamotozawan Series is absent at the type locality. Therefore, the definition of the Sakamotozawan Series has become ambiguous. However, the Pseudoschwagerina muongthensis Zone possibly corresponds to the lower part of Sakamotozawan Series that was defined as the lower Permian by the first occurrence of the genus Pseudoschwagerina. 8. Pseudofusulina vulgaris globosa Zone. The Pseudofusulina vulgaris globosa Zone is characterized by the abundance of Pseudofusulina vulgaris globosa (Schellwien). The lower part of this zone in Jigoku- dani area comprises Paraschwagerina spp. Limestones of this zone mostly consist of micritic matrices, but those near the base and top of this zone comprise sparry calcite cements with coarse grains. Change of lithofacies from the upper part of the under lying Pseudoschwagerina muongthensis Zone to the present zone is obvious, but the limestone sequence containing Paraschwagerina sp. and Pseudofusulina vulgaris globosa (Schellwien) seems to represent a nearly complete succession. The present zone is correlated with Pseudofusulina vulgaris Zone in other areas. This zone possibly cor responds to the upper or middle part of the Sakamotozawan Series. 9. Pseudofusulina aff. ambigua Zone. The Pseudofusulina aff. ambigua Zone is defined by the first occurrence of Pseudofusulina aff. ambigua (Deprat). Distribution of this zone is restricted to the bottom of Jigoku-dani, and therefore the detailed characters are not observed. The representative species of this zone is Pseudofusulina aff. ambigua (Deprat). This species is closely similar to Pseudofusulina ambigua of Deprat (1913), but it differs from the latter species in having a slightly larger proloculus and a more developed phrenothecae. In the Jigoku-dani area, Pseudofusulina aff. ambigua (Deprat) is associated with Pseudofusulina cf. vulgaris s. s. (Schellwien), which is similar to 46 Yasuhiro Ota

Pseudofusulina vulgaris of Schellwien (1909) and also resembles Chalaroschwagerina infiata of Skinner and Wilde (1965). This zone is tentatively compared with the strata containing the genus Chalaroschwagerina, but its precise stratigraphic position is unknown. In the Akiyoshi region, Toriyama (1954a, b, 1957, 1958) first divided Parafusulina Zone into the lower Pseudofusulina ambigua Subzone and the upper Parafusulina kaerimizensis Subzone. The present zone possibly corresponds to the previous Pseudofusulina ambigua Zone in the Akiyoshi Limestone Group.

-1-3. Conclusion In the Jigoku-dani area, the Akiyoshi Limestone Group is characterized by the following paleontological and lithological compositions and the author's studies led to the following conclusions. Biostratigraphically, limestones in this area are divided into the nine fusulina cean zones including seven subzones, ranging from the Middle Carboniferous to the Lower Permian. They are as follows in ascending order: 1. Fusulinella biconica Zone, 2. Fusulina cf. shikokuensis Zone, 2-1. Fusulinella cf. obesa Subzone, 2-2. Pseudofusu linella hidaensis Subzone, 3. Obsoletes obsoletus Zone, 3-1. Protriticites toriyamai Subzone, 3-2. Protriticites matsumotoi Subzone, 4. Montiparus sp. A Zone, 5. Triticites yayama dakensis Zone, 5-1. Triticites saurini Subzone, 5-2. Schwagerina sp. A Subzone, 5-3. Triticites biconicus Subzone, 6. Schwagerina (?) cf. satoi Zone, 7. Pseudoschwagerina muongthensis Zone, 8. Pseudofusulina vulgaris globosa Zone, 9. Pseudofusulina afT. ambigua Zone. The above listed zones are easily traceable in this area and indicate that these limestones are structurally inverted. Lithologically, limestones in this area have micritic matrices without biolithites. Sedimentary environment of limestones is considered to be lower energy environ ments like a lagoon within the Akiyoshi organic reef complex. Additionally, any remarkable stratigraphical gap, such as the lack of an important fossil zone, was not confirmed through the fusulinacean zones. This evidence indicates that the lagoonal limestones in the area were continuously accumulated through the Middle Carbon iferous and Lower Permian. In the Jigoku-dani area, Pseudoschwagerina muongthensis Zone is defined by the first occurrence of the inflated schwagerinids: pseudoschwagerinids, namely, the genus Pseudoschwagerina. The inflated schwagerinids including the genus Pseudoschwagerina are supposed to be planktonic during a part of their life cycle (Ross, 1982) and have world-wide distribution. Therefore, they are apparently excellent index fossils and are the most useful for the correlation of the Lowest Permian. The genus Pseudo schwagerina is known from some characteristic lithofacies, such as the biohermal lime stones (Ross, 1964). For regional correlation, the associated fossils are indispensable for determining the age and paleoenvironment. In this paper, the author prefers to correlate the limestones of the Pseudoschwagerina muongthensis Zone to the Lowest Fusulinacean Biostradgraphy of the Akiyoshi Limestone Group, Part I 47 48 Yasuhiro Ota

Permian by taking the first occurrence of the inflated schwagerinids (pseudo schwagerinids) into consideration.

-II-1. The second investigated AK area The second investigated AK area is located in front of the Akiyoshi-dai Museum of Natural History. The details of the stratigraphy and paleontology in this area have already been described by Y. Ota and M. Ota (1993). Here, the author reexamines the results of the investigation of the AK area, to compare with those of the Jigoku-dani area. The selected area represented by AK Traverse is in the normal sequence of the Akiyoshi Limestone Group (M. Ota, 1977). This traverse was established along the general trend, NE-SW (Fig. 18). The author had thin sections from rock samples of 56 localities and reexamined the biofacies and lithofacies.

-II-2. Results of the investigations -2-(l). Biofacies and Lithofacies The limestones are divided into two types by their color in the field. The first type is characterized by white limestone whereas the second one is black to dark gray color limestone. The former is subdivided into micrite, limestones with the sparry calcite cements and intermediate micritic limestone with micrite and sparry calcite cements. Dunham's classification (Dunham, 1962) of limestone is used for the present study. In the classification he emphasized that the limestone texture is important for the analysis of the energy condition. According to his classification, limestones along AK Traverse are recognized as the alternation of those of micritic matrices and sparry calcite cements. In addition the black to dark brown color limestones occur at AK 9, AK 11 and AK 12. The distribution ofsedimentary facies is shown in Fig. 19. Grain components consisting of abundant fusuhnaceans and phylloid algae were obtained from many localities in this area, and coarse grained limestones containing fragments of crinoids and bryozoans were interbedded in this limestone sequence (Fig. 20). Summarizing these facts, the sedimentary environment of this area is recon structed as the environment near an marginal lagoon within the Akiyoshi organic reef complex. -2-(2). Analysis of fusulinaceans along AK Traverse Almost all localities along AK Traverse yield many fusulinaceans. Lists of the identified fusulinaceans on AK Traverse and the composite stratigraphic sections with typical fusulinaceans are shown in Table 8 and Figs. 21, 22. On the basis of the fusulinaceans along AK Traverse, each horizon of this limestone sequence was characterized by the following fusulinacean subfamilies. AK 1-AK 6: Fusulinellinae Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 49

LEGEND

Micrite Matrix

Micritic Matrix

Sparry Calcite Cements

Black to Dark Brown Color Limestone

Fig. 19. Distribution of sedimentary facies along the AK Traverse. 50 Yasuhiro Ota

LEGEND

DEBRIS LIMESTONE INCLUDING CRINOIDS AND BRYOZOANS

FUSULINACEAN LIMESTONE

PHYLLOID ALGAL LIMESTONE

DASYCLADACEAN ALGAL LIMESTONE

LIMESTONE CONGLOMERATE 9 10 20 30

Fig. 20. Route map showing therepresentative biofacies and lithofacies of limestones along the AK Traverse. Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 51

Table 8. Distribution of the fusulinacean species in the AK area.

S^S;5>PWeS ^Localityt J ^4in!!110/o»03 11145fi 7fi01H22!22"Z33456 790 3332 4_3*44 71 _ 3 <

Fseudosctiwaaertna so. ______

AK 6-AK 9, and AK 11: Fusulininae and Fusulinellinae AK 9-AK 10 and AK 12-AK 25: Schwagerininae AK 25 and AK 35: Pseudoschwagerininae and Schwagerininae (+ Biwaellinae?: Sphaeroschwagerina (?)) AK 35-AK 41: Fusulinellinae (4-Schwagerininae?: Montiparus (?)) AK 41-AK 56: Schwagerininae ( +Fusulininae: Quasifusulina) Here, the author wants to pay special attention to the classification of fusulinaceans, because different opinions on the systematics of fusulinaceans are recognized in the obtained fusulinaceans. For examples: Obsoletes should be referred to Schwagerin inae (Rozovskaya, 1975; Sheng el al., 1988); Protriticites should be referred to Fusulininae (Sheng et al., 1988); Quasifusulina should be referred to Schwagerininae (Sheng etal., 1988). Based on modes of fusulinacean occurrences, namely transitions and characteris tics of the faunal elements and lithofacies of limestones, the following zones are Psflls. hidaensis '/.. Protriticites matsumotoi/.. Qfd. sp. A Z. Montiparus sp. A Z. Schwagerina sp. A Z. T. simplex /.. r. **>> > > >> row CD ro co o ^ —i L

n n c/> •5* re •n pi 5 5C re -1 9 f v: o 8 o n U &j T. 2 ps 7- s re 3 X Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 53

AK30.

Pseudofusulina vulgaris s. str. (Schellwien) AK29.

Pseudofusulina vulgaris I globosa (Schellwien) Schwagerina stablis (Rauser) AK2a

AK27. Pseudoschwagerina PseudoSchwaaerina sp Pseudoschwagerina AK2& morikawai Igo rseuoosenwagenna sp. muongthensis (Deprat)

Triticites ellipsoidalis Toriyama

Rugsochusenella (?) sp.

AK23.

AK22

,5 AK21

AK20

AK19 5M

AKia 1mm

Fig. 21-2. (Continued). r.-i Yasuhiro Ota

AK34. SSiS

Pseudofusulina sp.

AK33

AK3J Sphaeroschwagerina (?) sp.

5M AK31. 5__3 Schwagerina AK3a globulus japonicus Watanabe 1mm

Fig. 21-3. (Continued). discriminated in ascending order. 1. Pseudofusulinella hidaensis Zone 2. Protriticites matsumotoi Zone (s. 1.) 2-(2). Quasifusulinoides sp. A Zone 2-(l). Protriticites matsumotoi Zone (s. s.) 3. Montiparus sp. A Zone 4. Triticites simplex Zone (s. 1.) 4-(2). Triticites simp/ex Zone (s. s.) 4-(l). Schwagerina sp. A Zone 5. Pseudoschwagerina muongthensis Zone 6. Pseudofusulina vulgaris Zone The occurrence of these fusulinaceans and the limestone lithology support the conclusion that AK Traverse is composed of two nearly complete depositional se quences. The first sequence is recognized within AK 1 to AK 35, whereas the second sequence is recognized within AK 35 to AK 56. The maximum thickness of each zone within the sequences is shown in Table 9. Each zone is characterized by the following diagnostic fusulinaceans and stratig raphic features (Fig. 23) in ascending order. 1. Pseudofusulinella hidaensis Zone The Pseudofusulinella hidaensis Zone is characterized by the occurrence of Pseudofu- Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part 1 55

AK48 Triticites ozawai Toriyama Triticites michiae Toriyama

AK47

AK46-

AK45

AK44

AK41. AK40.

Quasifusulina sp. AK39

AK38.

AK37J

AK36. Montiparus (?) sp. Protriticites Protriticites matsumotoi matsumotoi (Kanmera) (Kanmera)

AK35

5M Triticites (?) all. Obsoletes Obsoletes sp. Montiparus (?) sp. yayamadakensis obsoletus evectus Kanmera (Schellwien)

1mm

Fig. 22-1. The composite stratigraphic section in the AK area (Second sequence). 56 Yasuhiro Ota

AK56. ; Schwagerina stabilis (Rauser)

x4 AK55.; Ozawainella sp.

Schwagerina cf. compact (White)

AK54.1 i Schwagerina stabilis (Rauser)

AK53.3

Schwagerina (?) sp.

AK52j

AK5tt

AK50. 2

AK49.1

x4 N - x4 ^55* x4 AK48. i Schubertella kingi Dunbar and Skinner Ozawainella sp. 1mm

Fig. 22-2. (Continued). Fusulinacean Biostratigraphyof the Akiyoshi Limestone Group, Part I 57

Table 9. The maximum thickness of each zone in the AK area.

Fusulinacean zone Thickness

6. Pseudofusulina vulgaris Zone (AK27-29) 13m

5. Pseudoschwagerina muongthensis Zone (AK25-27) (AK52-56) 11 m 34+ m

4. Triticites simplex Zone (s. 1.) 4-(2). Triticites simplex Zone (s. s.) (AK 18-25) (AK46-52) 35 m 42 m 4-(l). Schwagerina sp. A Zone (AK15-18) (AK41-46) 16m 20 m

3. Montiparus sp. A Zone (AK9-10, AK12-15) (AK37-41) 14m 12m

2. Protriticites matsumotoi Zone (s. 1.) 2-(2). Quasifusulinoides sp. A. Zone (AK8-9, AK11) 4 m 2-(l). Protriticites matsumotoi Zone (s. s.) (AK6-8) 13m

1. Pseudofusulinella hidaensis Zone (AK1-6) 34+m sulinella hidaensis (Kanuma) and the associated Fusulinella sp. This zone mainly con sists of white micrite limestone. 2. Protriticites matsumotoi Zone (s. 1.) The Protriticites matsumotoi Zone (s. 1.) is characterized by the occurrence of Protriticites matsumotoi (Kanmera). This zone is subdivided into two zones, namely, the lower, the Protriticites matsumotoi Zone (s. s.) characterized by Protriticites matsumotoi (Kanmera), and the upper, the Quasifusulinoides sp. A Zone, characterized by Quasifusulinoides sp. A. The genus Quasifusulinoides was not confirmed from the second sequence in AK Traverse. The Quasifusulinoides Zone reported by Ueno (1989) is supposed to be restricted. Therefore, Quasifusulinoides sp. A. Zone is tentatively discriminated and it is included in the Protriticites matsumotoi Zone (s. 1.) be cause the main fusulinacean constituents of the present two zones belong to Fusu linellinae and Fusulininae. 2-(l). Protriticites matsumotoi Zone (s. s.) The Protriticites matsumotoi Zone (s. s.) yields Obsoletes obsoletus (Schellwien), Protriticites matsumotoi (Kanmera) and Triticites (?) aff.yayamadakensis evectus Kanmera. Triticites (?) aff. yayamadakensis evectus Kanmera resembles the Late Carboniferous Triticitesyayamadakensis evectus Kanmera from the Yayamadake Limestone, Kumamoto Prefecture in general shape. However, the stratigraphic horizon of the present spe cies is higher than those of the closely related ones from Jigoku-dani and Yayama dake, because the present species is associated with Obsoletes obsoletus (Schellwien). The limestones with these species commonly have limestones with micritic ma trices. Limestones with sparry calcite cements are distributed near the lower boundary of the Protriticites matsumotoi Zone (s. s.). There is a tendency of increased micritic matrices toward the upper part of this zone. 58 Yasuhiro Ota

Zone Species

Pseudofusulina vulgaris Zone Pseudofusulina vulgaris s. s. (Schellwien), Pseudofusulina vulgaris globosa (Schellwien), Pseudofusulina sp., Sphaeroschwagerina (?) sp., Triticites complicatus Rozovskaya

Pseudoschwagerina muongthensis Zone Pseudoschwagerina muongthensis (Deprat), Pseudoschwagerina morikawai Igo, Pseudoschwagerina sp., Triticites ellipsoidalis Toriyamai, Schwagerina cf. compacts (White), Schwagerina stabilis (Rauser), AugosochuseneJ/a (?) sp., Schubertella kingi Dunbar and Skinner

Triticites simplex Zone (s. 1.) Triticites cf. secalicus (Say), Triticites simplex Zone (s. s.) Triticites ozawaiToriyama, Triticites michiaeToriyama, Trinities cf. paraarcticus Rauser, Schubertella kingi Dunbar and Skinner, OzawaineHa sp.

Schwagerina sp. A Zone Triticites biconicusToriyama, Triticites cf. saurini Igo, Triticites ozawaiToriyama, Triticites exsculptus Igo, Triticites sp. B, Triticites sp.C, Schwagerina sp. A, Quasifusulina sp. A, Quasifusulina sp., Ozawainella sp.

Montiparus sp. A Zone Triticites sp. A, Triticites (?) sp., Sciitvageriiiaf?) sp. A, Montiparus sp. A, Montiparus (?) sp. A, Protriticites matsumotoi (Kanmera)?

fro(ritrcires matsumoroi Zone (s. 1.) Quasifusulinoides sp. A Quasifusulinoides sp. A Zone Quasifusulinoides sp.

Protriticites matsumotoi Zone(s. s.) Triticites (?) aff. yayamadakensis evectus Kanmera, ft-otrific/res matsumotoi (Kanmera), Ohso/eres obsoletus (Schellwien)

Pseudofusulinella hidaensis Zone Pseudofusulinella hidaensis (Kanuma)

Fig. 23. Fusulinacean zones and the faunal elements of each zone in the AK area.

2-(2). Quasifusulinoides sp. A Zone The Quasifusulinoides sp. A Zone is discriminated by the first occurrence of Quasifusulinoides sp. A. This zone is only confirmed in the first sequence in AK Tra verse with a maximum thickness of about 4 m. 3. Montiparus sp. A Zone The diagnostic species of this zone is Montiparus sp. A, and the associated fossils are as follows: Protriticites matsumotoi (Kanmera), Montiparus (?) sp. A, Schwagerina (?) sp. A, Triticites sp. A, and Triticites (?) sp. In this zone limestones with sparry calcite cements gradually change to micritic in the upper part of the section. Protriticites matsumotoi (Kanmera) was found in limestones with sparry calcite cements in the lower part of the present zone. The occurrence ofProtriticites matsumotoi (Kanmera) which is the diagnostic species of the underlying zone probably reveals that Protriticites matsumotoi (Kanmera) and other associated species are derived from the Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 59

underlying limestones. 4. Triticites simplex Zone (s. 1.) The Triticites simplex Zone (s. 1.) is characterized by the occurrence of Triticites and Schwagerina, comparing with the Triticites-Schwagerina Zone (s. s.). 4-(l). Schwagerina sp. A Zone The Schwagerina sp. A Zone is characterized by the predominance of Schwagerina sp. A. The lower boundary of this zone in the first sequence in AK Traverse is drawn at the horizon characterized by the occurrence of Triticites exsculptus Igo, Triticites ozawai Toriyama and Triticites cf. saurini Igo, whereas that of this zone in the second sequence is tentatively drawn at the horizon where Quasifusulina sp. occurs and lithofacies change from limestones with micrite matrices to those with sparry calcite cements. Schwagerina sp. A is similar to Rugosofusulina sp. A reported by Hasegawa (1988). However, the former is distinguished from the latter by its very weak rugosity of wall. The specific constituents of this zone are as follows: Ozawainella sp., Quasifusulina sp. A, Quasifusulina sp., Triticites biconicus Toriyama, Triticites exsculptus Igo, Triticites ozawaiToriyama, Triticites cf. saurini Igo, Triticites sp. B and Triticites sp. C. The lower part of the present zone is predominant in limestones with sparry calcite cements and these contain Schwagerina sp. A. Limestones with micrite matrices increase toward the upper part of this zone. 4-(2). Triticites simplex Zone (s. s.) In the AK area, Triticites simplex (Schellwien) was not confirmed. However, the specific assemblages of fusulinaceans identify them as members of Triticites simplex Zone (s. s.), which is equivalent to the upper part of the Triticites simplex Zone (s. 1.) (M. Ota, 1977). The following fusulinaceans are common in this zone: Ozawainella sp., Schubertella kingi Dunbar and Skinner, Schubertella sp., Schwagerina sp., Triticites michiae Toriyama, Triticites ozawai Toriyama, Triticites cf. secalicus (Say) and Triticites cf. paraarcticus Rauser. This zone mainly consists of limestones with micritic matri ces. Limestones with sparry calcite cements appear and are interbedded with the micritic ones in the upper part of this zone. The energy condition of the depositional environment is considered to have shifted from lower to higher. 5. Pseudoschwagerina muongthensis Zone The Pseudoschwagerina muongthensis Zone is characterized by the occurrence of Pseudoschwagerina muongthensis (Deprat) and the lower boundary of this zone is defined by the first appearance of Pseudoschwagerina (Pseudoschwagerina morikawai Igo). Along the first sequence of AK Traverse, Pseudoschwagerina morikawai Igo, the microspheric form first occurs at a horizon about 8 m lower than that of Pseudoschwagerina muongth ensis (Deprat), the megalospheric form. However, Pseudoschwagerina muongthensis (Deprat) is associated with Pseudoschwagerina morikawai Igo at AK 26. Furthermore, the boundary of the Pseudoschwagerina muongthensis Zone with the underlying zone was formerly drawn by the first occurrences of Pseudoschwagerina [Pseudoschwagerina 60 Yasuhiro Ota muongthensis (Deprat)], including megalospheric and microspheric forms. There fore, the base of the present Pseudoschwagerina muongthensis Zone is demarcated by the first occurrence of the inflated schwagerinid, Pseudoschwagerina. Along the second sequence, Pseudoschwagerina was not found, but the zone was recognized from a hori zon (AK 52), where advanced fusulinaceans occurred. Limestones of the first sequence yield the following fusulinaceans: Pseudo schwagerina muongthensis (Deprat), Pseudoschwagerina morikawai Igo, Pseudoschwagerina

Fig. 24. Distribution of fusulinacean zones in the AK area (modified from Hasegawa, 1992). Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 61 sp., Rugosochusenella (?) sp., Triticites ellipsoidalis Toriyama and Schwagerina stabilis (Rauser). The second sequence yields Schwagerina stabilis (Rauser), Schwagerina cf. compacta (White), Schwagerina (?) sp., Schubertella kingi Dunbar and Skinner, and Ozawainella sp. This zone is, as a whole, composed of micritic limestones except for the upper part. Limestones across the boundary between the present zone and the underlying zone along the first sequence change upward from those with sparry calcite cements to micritic. Limestones along the second sequence, however, are mainly composed of micritic limestones on both sides of the boundary. Limestones with sparry calcite cements are common in the upper part of the present zone. They suggest a relative ly high energy environment and yield abundant Schwagerina, such as Schwagerina stabilis (Rauser). The lack of limestones with sparry calcite cements near the lower boundary of the Pseudoschwagerina muongthensis Zone in the second sequence, probably suggest that these micritic limestones were accumulated in an environment in which the inflated schwagerinids, i.e. Pseudoschwagerina, could not exist. 6. Pseudofusulina vulgaris Zone The Pseudofusulina vulgaris Zone in the AK area is characterized by the diagnostic species, Pseudofusulina vulgaris (Schellwien), and the following associated species, Triticites complicatus Rozovskaya, Sphaeroschwagerina (?) sp., Pseudofusulina vulgaris globosa (Schellwien) and Pseudofusulina sp. This zone is characterized by limestones with the micritic matrices. From distribution of the zones (Fig. 24), it has become clear that the succession of AK Traverse consists of two nearly complete limestone sequences, possibly separated by the NE- SW fault (shown by Ozawa and Kobayashi, 1990).

-II-3. Correlation -3-(l). Correlation (Within Japan) In this chapter the author presents the tentative correlation of fusulinacean zones of the Akiyoshi Limestone Group of the AK area and a reference proposal for the subdivision of the Middle Carboniferous and Lower Permian fusulinacean zones (shown in Fig. 17). 1. Pseudofusulinella hidaensis Zone The characteristic species of this zone is Pseudofusulinella hidaensis (Kanuma), originally described by Kanuma (1953) as Wedekindellina (?) hidaensis. Ozawa and Kobayashi (1990) first treated this species under the generic name of Pseudofusulinella and established the Pseudofusulinella hidaensis Zone with the diagnostic species. The phylogenetic trend of Pseudofusulinella was studied by Ozawa (1967) and Wilde (1971). According to Kanuma (1953), this species has a small elongate fusiform shell with a straight axis of coiling, inflated central area, bluntly pointed poles and slightly concave lateral slopes. In addition chomata are large and massive, and axial fillings are well developed. Wedekindellina Dunbar and Henbest, 1933 is char- 62 Yasuhiro Ota

acterized by its elongated small shell, and well developed axial fillings and four lay ered wall with perforations. To the contrary, Pseudofusulinella Thompson, 1951 has a spirotheca composed of a tectum and diaphanotheca with very minute but distinct pores. The massive chomata in the center of the shell cover the lower surfaces of spirotheca to give it the appearance of spirotheca of four layers as found in Fusulinella and Fusulina. Pseudofusulinella is distinguished from Fusulinella by its younger occur rences than the latter and by having different features of the wall and axial fillings. From its general shapes and features, the obtained specimen should be referable to Pseudofusulinella hidaensis (Kanuma). The Pseudofusulinella hidaensis Zone of the author is correlated with the same zone by Ozawa and Kobayashi (1990). In this inves tigated AK Traverse, Beedeina akiyoshiensis (Toriyama) which is the diagnostic species of the Beedeina akiyoshiensis Zone (M. Ota, 1977) was not confirmed. Hence it is very difficult to directly correlate the Pseudofusulinella hidaensis Zone with the Beedeina akiyoshiensis Zone. Nevertheless the present zone corresponds to the Beedeina akiyoshiensis Zone based on biostratigraphic relationship between the present zone and the underlying and overlying zones. Ueno (1989) recognized the Beedeina akiyoshi ensis Zone between the upper, Fusulinella taishakuensis Zone and the lower, Protriticites sp. Zone. According to him, only Pseudofusulinella sp. (sp. nov.?) was reported from Protriticites sp. Zone. Ueno (1991b) reported that Pseudofusulinella (Kanmeraia) praeantiqua Nassichuk and Wilde was found in the uppermost part of the Protriticites sp. Zone and the lower part of the Quasifusulinoides toriyamai Zone (Ueno, 1989), but the detailed relationships between the Pseudofusulinella hidaensis Zone and these zones are not clear. However, Fusulinella biconica Zone is correlative with the Fusulinella biconica Zone of Hasegawa (1988) and Ozawa and Kobayashi (1990). On the other hand, the Fusulinella taishakuensis Zone was first introduced by Okimura (1987) and is characterized by the occurrence of Fusulinella taishakuensis established by Sada and Yokoyama (1970). The Fusulinella taishakuensis Zone is associated with the following fusulinaceans: Fusulinella biconica (Hayasaka), Fusulinella simplicata Tori yama, Fusulinella bocki Moller and Fusulinella subsphaerica Toriyama. Judging from the constituents of the preceding zones, the Fusulinella taishakuensis Zone and the Fusulinella biconica Zone (Ueno, 1989) correspond to the Fusulinella biconica Zone (M. Ota, 1977). 2. Protriticites matsumotoi Zone (s. 1.) 2-(l). Protriticites matsumotoi Zone (s. s.) Protriticites matsumotoi (Kanmera) is the diagnostic species of this zone. This species was described by Kanmera (1955) as a representative species of Hikawan Series and is known as a primitive species of this genus. In well preserved speci mens of Protriticites matsumotoi (Kanmera), the spirotheca of the third to the fourth and occasionally the fifth volutions appear to be composed of four layers. The spirothecal characters closely resemble those of Fusulinella Moller. In mature specimens, the spirotheca of the fifth to mature volutions have a clearly discernible Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 63 keriotheca. The classification of Triticites (s. 1.) and its evolution have been discussed since Rozovskaya (1948) classified Triticites (s. 1.) into four subgenera, Triticites (s. s.), Montiparus, Rauserites and Jigulites. Some considerations concerned with their several variations are present. One variation is the "Protriticites-type wall". Rauser and Fursenko (1959) described the wall structure of Protriticites that it is perforated and composed of four-layers in the inner volutions and three-layers in outer ones, namely a tectum, protheca and outer tectorium. The same structure of Protriticites was also noticed by Loeblich and Tappan (1988). Sheng, Zhang and Wang (1988) also confirmed that the inner spirotheca of Protriticites were composed of four layers like Fusulinella, but the outer spirotheca were composed of a tectum and the inner and outer tectoria. They also mentioned that Protriticites was an intermediate form between Fusulinella and Triticites (s. s.). Rozovskaya (1950) clearly illustrated the keriothecal wall in Protriticites. Putrya (1948) remarked on the complicated wall of Protriticites in his original description of the genus. He noticed that it is composed of a tectum, diaphanotheca and two tectoria. Furthermore, he noticed that the diaphanotheca, tectoria and chomata possess the structure of fine alveoli, and the coarser ones are recognizable in the inner tectorium. In the outermost whorl the alveolers structure reaches diaphanotheca. Davydov (1990) proposed the lineage from Protriticites to Rauserites, through Montiparus. According to him, the inner tectorium which is considered as a characteristic feature of Montiparus is only present in the inner whorls where the keriothecal wall is not present. Summarizing preceding evidence, it is noticed that Protriticites has the inner tectorium in the outer volution and if we recognize the inner tectorium in outer volution of a specimen, then it might belong to Protriticites. Triticites (s. 1.) matsumotoi by Kanmera (1955) has a Protriticites-type wall only in the outer volutions. Based on these facts, the author treats this species under Protriticites. Hasegawa (1988) treated this species as the diagnostic species of the Triticites matsumotoi Subzone. According to hisopinions, this species has very primitive features of Triticites (s. 1.). Additionally, the fauna of the Triticites (s. 1.) matsumotoi Zone is missing in some areas. The fauna of the Triticites simplex Zone directly overlies the Fusulinella-Fusulina Zone in some cases. Therefore, he interpreted that Protriticites was able to migrate to the place where a fusulinacean favorable environment appeared in the early stage. Recently, a primitive-Triticites (s. 1.) fauna, including Protriticites, was reported from the Akiyoshi region and some other districts. Hence, the author correlated the Protriticites matsumotoi Zone (s. s.) with limestones, bearing species of primitive Triticites (s. 1.). The present Protriticites matsumotoi Zone (s. s.) corresponds to the Triticites (s. 1.) matsumotoi Zone (M. Ota, 1977), the Triticites matsumotoi Zone (Hasegawa, 1988) and the Protriticites sp. Zone (Ueno, 1989). Furthermore it is correlative with the Obsoletes obsoletus Zone (Watanabe, 1991) and the Protriticites (P.) matsumotoi Zone (Ishii, 1990). 64 Yasuhiro Ota

2-(2). Quasifusulinoides sp. A Zone The Quasifusulinoides sp. A Zone is characterized by the occurrence of Quasifusuli noides. The occurrence of this zone is restricted and thus it is included in the Protriticites matsumotoi Zone (s. 1.) on the basis of its confined distribution and the stratigraphic relationship between the overlying and underlying zones. Ueno (1989) established the Quasifusulinoides toriyamai Zone and this zone is correlated with the Quasifusulinoides sp. A Zone. The present zone may be also equivalent to the lower part of the Montiparus montiparus-Quasifusulinoides ohtanii Zone (Ozawa and Kobayashi, 1990) and the upper part of the Obsoletes obsoletus Zone (Watanabe, 1991). In the Jigoku-dani area, well-preserved Quasifusulinoides do not occur, but Quasifusulinoides (?) sp. was obtained from the Protriticites matsumotoi Subzone. Therefore, the present Quasifusulinoides sp. A Zone probably corresponds to the Protriticites matsumotoi Sub- zone of the Jigoku-dani area. 3. Montiparus sp. A Zone This datum level is defined by the occurrence of Montiparus. As mentioned before, Montiparus was first introduced as a subgenus in four subgenera of Triticites (s. 1.) with Triticites montiparus Ehr. em. Moell. as the type species by Rozovskaya (1948). However, the variations and definitions of Montiparus are ambiguous, and some disagreements about the genus are present. Wilde (1984) treated Montiparus Rozovskaya, 1948 as a synonym of Schwagerina montipara (Ehrenberg, 1854) emend. Dunbar and Skinner, 1936, and proposed the new name of Eotriticites. In short, Montiparus has historically two different types and thus the definition of Montiparus is unclear. The obtained specimens should be referred to Montiparus Rozovskaya, 1948 with the following type species, Triticites (Montiparus) montiparus Rozovskaya, 1948=Fusulina montipara Ehrenberg emend. Moller, 1878. Montiparus sp. A is a diagnostic species of the Montiparus sp. A Zone. The Montiparus sp. A Zone is also associated with Protriticites matsumotoi (Kan mera), Montiparus (?) sp. A, Schwagerina (?) sp. A, Triticites sp. A and Triticites (?) sp. This zone is correlated with the lower part of the Triticites simplex Zone (M. Ota, 1977), because Triticites in the present zone has a relatively primitive form. More over, this zone probably corresponds to the upper Montiparus montiparus-Quasifusuli noides ohtanii Zone and the Montiparus matsumotoi Zone (Ozawa and Kobayashi, 1990), the Triticites yayamadakensis Zone (Ishii, 1990) and the lower part of the Triticites simplex Zone (Hasegawa, 1988). 4. Triticites simplex Zone (s. 1.) 4-(l). Schwagerina sp. A Zone The Schwagerina sp. A Zone is distinguished by the characteristic occurrence of Schwagerina sp. A. This zone is associated with occurrences of the following species: Triticites biconicus Toriyama, Triticites exsculptus Igo, Triticites ozawai Toriyama, Triticites cf. saurini Igo, Triticites sp. B, Triticites sp. C, Quasifusulina sp. A, Quasifusulina sp. and Ozawainella sp. Zhang (1991) placed the Triticites-Schwagerina Zone under Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 65

Pseudoschwagerina Zone and reported the first occurrence of Schwagerina in the lower part of the Triticites siuckenbergi Zone. Kanmera, Ishii and Toriyama (1976) also established the Schwagerina Zone under the Pseudoschwagerina Zone. The present Schwagerina sp. A Zone corresponds to Triticites-Schwagerina Zone (s. s.) and is tenta tively correlated with the lower parts of the Triticites simplex Zone (M. Ota, 1977) and the Triticites yayamadakensis Zone in the Jigoku-dani area. 4-(2). Triticites simplex Zone (s. s.) The specific constituents of the Triticites simplex Zone (s. s.) are as follows: Ozawainella sp., Schubertella kingi Dunbar and Skinner, Schubertella sp., Schwagerina sp., Triticites michiae Toriyama, Triticites ozawai Toriyama, Triticites cf. paraarcticus Rauser and Triticites cf. secalicus (Say). Unfortunately, Triticites simplex (Schellwien) was not collected in this investigation. However, judging from the coexisted fusulina ceans, the specific assemblage corresponds to that of the upper part of Triticites simplex Zone (M. Ota, 1977). It is also similar to those from the upper part of the Triticites yayamadakensis Zone to Schwagerina (?) cf. satoi Zone of the Jigoku-dani area. In addition, the Triticites simplex Zone (s. s.) is correlated with the upper part of the Triticites hidensis Zone (Ishii, 1990), the Triticites (Rauserites) paraarcticus and Triticites (Rauserites) siuckenbergi Zones (Ozawa and Kobayashi, 1990), the upper part of the Triticites simplex Zone (Hasegawa, 1988) and the upper Triticites "simplex" Zone (Ueno, 1989). 5. Pseudoschwagerina muongthensis Zone The Pseudoschwagerina Zone was formerly divided into two subzones by Toriyama (1954a), namely the lower Triticites simplex Subzone and the upper Pseudofusulina vulgaris Subzone (Toriyama, 1954a). Hasegawa (1963) subdivided the Pseudo schwagerina Zone into two subzones, the lower, the Triticites simplex Subzone and the upper, the Pseudoschwagerina muongthensis Subzone. The Pseudoschwagerina muongthensis Subzone was treated as the Pseudoschwagerina (P.) muongthensis Zone, and the Triticites simplex Subzone as the Triticites simplex Zone by M. Ota (1977). The datum level of this zone is formerly demarcated by the first occurrence of inflated schwagerinids, i.e. Pseudoschwagerina muongthensis (Deprat), including megalospheric and microspheric forms. Therefore, the lowest part of the present zone in the AK area coincides with the occurrence of Pseudoschwagerina morikawai Igo. Many fusulinacean workers have studied before on the inflated schwagerinids and their paleoecology and paleobiogeography. Studies on their provinciality were also presented by Ross (1962, 1963a, 1964, 1967, 1982) and Gobbett (1973). Ross (1982) mentioned that several genera among the schwagerinids were probably planktonic during a part of their life cycles. Ross (1962, 1963a, 1964, 1967) examined their evolution, migrations and dispersal in detail. Ross (1967, 1973) pointed out the difference of each province based on the paleobiogeographic separation of fusulinid faunas and also discussed the lineage of Protriticites. A lineage with Montiparus-Obsoletes-Triticites was confirmed only in the Eurasian- Arctic province. Whereas only Triticites was recognized at the 66 Yasuhiro Ota same stratigraphic positions in Mid-continent province. Ross (1962, 1963a, 1964) classified the pseudoschwagerinids into eight complexes and he discussed their details. From these studies, he concluded that the greatest diversity of them took place in the Tethyan seaway in later Wolfcampian time. On the other hand, Gobbett (1973) discussed Pseudoschwagerina as a cosmopolitan genus. As mentioned above, it is very effective to use the datum level defined by the first occurrence of the inflated schwagerinids for accurate global correlation. Rui and Zhang (1987) also noticed that pseudoschwagerinids might be used for global correlation, owing to their rapid evolution and global distribution. The correlation of the Pseudoschwagerina Zone has been discussed by many authors, such as Hanzawa (1942), Hayasaka and Minato (1954), Fujimoto (1959), Fomichev (1960), Kahler (1961), Rauser (1965) and Lapkin and Kats (1990). Although the inflated schwagerinids show global distribution, their occurrence seems to be restricted to somewhat coarser sediments. Evidences for this was given by Ross (1964). Therefore, examination of their accompanying fossils is indispensable for accurate correlation. The present zone is correlated with the Pseudoschwagerina (P.) muongthensis Zone (M. Ota, 1977), and the Pseudoschwagerina muongthensis Zone in the Jigoku-dani area. The lower boundary of this zone approximately coincides with those of the Sphaeroschwagerina fusiformis Zone (Ishii, 1990, Watanabe, 1991), the "Sphaeroschwagerina" fusiformis Zone (Ozawa and Kobayashi, 1990) and the Alpinoschwagerina (?)fusiformis Zone (Ueno, 1989). 6. Pseudofusulina vulgaris Zone The base of this zone is marked by the occurrence of the diagnostic species, Pseudofusulina ex. gr. vulgaris (Schellwien). Several studies of the systematics of Pseudofusulina have been carried out internationally. Davydov (1988a, b) examined in detail the origin and development of the pseudofusulinids. However, discussions on the systematics, classification and stratigraphic significance of the pseudofusu linids still continue. Zhang (1983, 1991) discriminated "Pseudofusulina Bed" under the Pseudoschwagerina Zone, and correlated this bed with lower Daixina sokensis Zone. According to him, Pseudofusulina stratigraphically occurs in a bed lower than that bearing Pseudoschwagerina. Rauser (1951) recognized the Pseudofusulina Horizon beneath the Schwagerina Horizon in association with primitive species of Triticites. In the "Pseudofusulina Horizon", the earliest pseudofusulinids, i.e. Pseudofusulina krotowi (Schellwien) and Pseudofusulina paragregaria Rauser occur. Naoumova and Rauser (1964) reported the occurrence of two different types of these Pseudofusulina from different stratigraphic horizons. Because of different reports, the correlation of the Pseudofusulina Zone is very difficult. An urgent task is the clarification of the origin and phylogeny of Pseudofusulina. The present Pseudofusulina vulgaris Zone corresponds to the Pseudofusulina vulgaris Zone (M. Ota, 1977), the Pseudofusulina vulgaris Subzone (Hasegawa, 1988), the Pseudofusulina ex. gr. vulgaris Zone (Ueno, 1989), the Chalaroschwagerina vulgaris Zone (Ishii, 1990), the Paraschwagerina akiyoshiensis-Pseudofusulina firm Zone, the Robusto- Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 67

schwagerina schellwieni pamirica-Schwagerina krotowi Zone and the Robustoschwagerina schellwieni schellwieni-Pseudofusulina vulgaris vulgaris Zone (Watanabe, 1991), and the Dutkevitchia splendida Zone and Pseudofusulina vulgaris Zone (Ozawa and Kobayashi, 1990). -3-(2). Correlation (International) In this chapter, tentative correlation between the investigated AK area and the reference sections is examined. The name of the Carboniferous is derived from England, and the name of Permian from "Perm" to the west of the Ural Mountains. The Carboniferous and Permian Systems were established in different areas with different facies. There is so far no consensus of the definition of the boundary between the two systems. Therefore, each worker has applied his own definition to each stratigraphical division. Even in the stratotype, several proposals for its division are present. Because of this situation, the refinement of biostratigraphic units and accurate international correlation of the Upper Carboniferous and Lower Permian seems to be difficult and chaotic. The following zones along AK Traverse are tentatively correlated with the biostratigraphic units in the reference sections (Fig. 25). 1. Pseudofusulinella hidaensis Zone This zone is characterized by Pseudofusulinella hidaensis (Kanuma). It is accom panied by Fusulina sp. Although Ozawa and Kobayashi (1990) first introduced the Pseudofusulinella hidensis Zone, this zone is not confirmed in many areas. The Pseudofusulinella hidaensis Zone is correlative with the bed over the Fusulinella Zone. Wilde (1971, 1975, 1984) classified Pseudofusulinella into four specific groups (Group I: elongate-fusiform species with perched chomata, Group II: small, very slender- fusiform species with perched chomata, Group III: intermediate, thickly fusiform species with perched chomata, Group IV: large, thickly fusiform species with massive chomata). Pseudofusulinella hidaensis (Kanuma) probably belongs to Group I: Species with elongate-fusiform shell with perched chomata. This zone is possibly correlated with his Zone A and Zone 1 (Wilde, 1984). Ross (1984) noticed that Pseudofusu linella is sometimes accompanied by lower Permian Schwagerina, and these species of Pseudofusulinella may be relicts of their Carboniferous ancestors. Gobbett (1973) emphasized that Pseudofusulinella belongs to an element of the boreal fauna and the occurrence is confined to the Lower Permian. Rui, Ross and Nassichuk (1991) discussed the paleobiogeography of late Moscovian (Desmoinesian) age and discrim inated four climatic zones and fusulinacean provinces. They mentioned that both Wedekindellina and Pseudoendothyra are representative of the Arctic province, whereas Beedeina, Fusulina, and Neostaffella are characteristic genera of the Tethyan province. Beedeina was not found along AK Traverse and JI Traverse, and the problem of the faunal province of the Pseudofusulinella hidaensis Zone and its detailed stratigraphic position continues to be unclear. However, this zone is possibly correlated with the preceding Fusulina-Beedeina Zone and the bed under the Zone 1 and Zone A by Wilde 68 Yasuhiro Ota

(1984). 2. Protriticites matsumotoi Zone (s. 1.) This zone is characterized by the occurrence of Protriticites matsumotoi (Kanmera). The upper part of this zone in the first sequence contains Quasifusulinoides sp. A. The distribution of Quasifusulinoides sp. A is definite, so the present zone is tentatively subdivided into two zones the lower, the Protriticites matsumotoi Zone (s. s.) and the upper, the Quasifusulinoides sp. A Zone. 2-(l). Protriticites matsumotoi Zone (s. s.) This zone is defined by the occurrence of characteristic species, Protriticites matsumotoi (Kanmera). This zone is correlative with beds of other areas, bearing Protriticites. Davydov (1990) showed a lineage of Fusulinella- Protriticites-Montiparus- Rauserites and established the Protriticites pseudomontiparus-Obsoletes obsoletus Zone over the Fusulinella bocki-Fusulina eopulchra-Fusulina cylindrica Zone. The Protriticites matsumo toi Zone is correlated with the Protriticites pseudomontiparus Zone (Davydov, 1990) from the associated fusulinaceans, such as Obsoletes obsoletus (Schellwien). Ross and Ross (1985b, 1988) recognized the Obsoletes obsoletus Zone under the Quasifusulinoides- Protriticites pseudomontiparus Zone. Ozawa and Kobayashi (1990) also discriminated the Obsoletes obsoletus Zone under the Protriticites subschwagerinoides Zone in the Akiyoshi Limestone Group. In the AK area, Obsoletes obsoletus (Schellwien) was found within the biohorizon of the first appearance of Protriticites matsumotoi (Kanmera). Watanabe (1991) established the Obsoletes obsoletus Zone which is correlative with the Protriticites matsumotoi Zone (s. 1.). Davydov (1990) proposed that the boundary between the Middle and Upper Carboniferous should be drawn at the biohorizon which is characterized by the first appearance of Protriticites. Rauser and Shcher- bovich (1974) drew the boundary between the Moscovian and Kassimovian Stage at the lower boundary of the Protriticites Zone. Ross and Ross (1985b, 1988) recognized the Fusulina cylindrica-Protriticites ovoides Zone under the Obsoletes obsoletus Zone. The present Protriticites matsumotoi Zone (s. s.) is correlative with the lower part of the Protriticites pseudomontiparus-Obsoletes obsoletus Zone (Leven, 1979, 1980a, 1981; Leven and Shcherbovich, 1978; Winkler, 1990), the lower part of the Eowaeringella Zone (Wilde, 1984), the lower part of the Quasifusulinoides, Eowaeringella, Oketaella Zone (Ross and Ross, 1985b, 1987, 1988), the lower part of the Protriticites sub schwagerinoides Zone (Zhou et al., 1987), the lower part of the Protriticites-Obsoletes assemblage Zone (Zhang, 1983, 1991) and the lower part of the Obsoletes-Montiparus Subzone (Ding et al., 1991). 2-(2). Quasifusulinoides sp. A Zone This zone is tentatively defined by the first occurrence of Quasifusulinoides. The name Quasifusulinoides was first introduced as Fusulina ex. gr. quasifusulinoides- Quasi fusulinoides- Quasifusulina in the table of M. -Maklay, Rauser and Rozovskaya (1958). After then, Quasifusulinoides was described by Rauser and Fursenko (1959) with Pseudotriticites fusiformis Rozovskaya, 1952 as the type species. Chen (1963)

Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 69 and Nikitina (1969) treated Quasifusulinoides as a subgenus of Fusulina. M. -Maklay (1963) considered this genus as a synonym of Pseudotriticites. According to Thomp son (1964), the difference between Quasifusulina Chen, 1934 and Quasifusulinoides cannot be recognized. Sheng, Zhang and Wang (1988) noticed that Quasifusuli noides should be included in Fusulina. Rozovskaya (1975) treated Quasifusulinoides as a valid name, and Pseudotriticites as a synonym of Fusulina. Ueno (1991b) stated that Quasifusulinoides could be distinguished from Fusulina by its wall with fine perforation and its younger stratigraphic occurrence than the latter. Ginkel and Villa (1991) agreed to treat Quasifusulinoides as Fusulina (Quasifusulinoides). In short, the differ ences between Fusulina and Quasifusulinoides were treated as those of subgeneric level. Collected specimens of Quasifusulinoides sp. A from AK Traverse have advanced wall with tectum, "protheca" and inner tectorium, and the wall structure is similar to that of the genus Fusulina. Thus Quasifusulinoides is considered to belong to Fusulininae. Furthermore, the stratigraphic occurrence is higher than that of Fusulina, because Quasifusulinoides sp. A was found above the level of the first appearance of Protriticites matsumotoi (Kanmera). As the distribution of this zone is narrow and restricted, detailed correlation is difficult. However, Davydov (1990) noticed the coccurrence of Quasifusulinoides with Fusulinella and Protriticites, and he proposed the boundary between the Middle and Upper Carboniferous at a level of the first appearance of Protriticites. Therefore, this zone is correlative with the Protriticites pseudomontiparus- Obsoletes obsoletus Zone. Ross and Ross (1985b, 1987, 1988) recognized the Quasifusu linoides Zone and Protriticites pseudomontiparus Zone over the Obsoletes obsoletus Zone in N. W. Europe, Moscow Basin and southern Ural. The present Quasifusulinoides sp. A Zone is correlated with the above Quasifusulinoides Zone and Protriticites pseudomonti parus Zone, and more probably with the upper part of the Protriticites pseudomontiparus- Obsoletes obsoletus Zone of Russia (Leven, 1980a, b, 1981; Leven and Shcherbovich, 1978; Winkler, 1990), the upper part of the Eowaeringella Zone of U. S. A. (Wilde, 1984), the upper part of the Quasifusulinoides, Eowaeringella, Oketaella Zones of the southwestern United State (Ross and Ross, 1985b, 1987, 1988), the upper part of the Protriticites subschwagerinoides Zone of South China (Zhou et al., 1987), the upper part of the Protriticites-Obsoletes assemblage Zone summarized by Zhang (1983, 1991), and the middle part of the Obsoletes-Montiparus Zone of North China (Ding et al., 1991). 3. Montiparus sp. A Zone The Montiparus sp. A Zone is characterized by the occurrence of Montiparus, and correlated with the Montiparus Zone in other areas. Zhang (1984) divided the Permian in South China into the following three stages, based on the fusulinacean wall structure. (1). Pre-keriotheca stage (Fusulina: Dalan Stage). (2). Keriotheca stage (Montiparus, Triticites, Pseudoschwagerina, Sphaeroschwagerina, Robustoschwagerina: a. Mapingian Stage; Pseudofusulina: b. Xiangzhongian Stage; Misellina: c. Qixian Stage; Cancellina, Neoschwagerina, Yabeina: d. Maokouan Stage). 70 Yasuhiro Ota

(3). Post-keriotheca stage (Codonofiisiella: a. Sanyangian Stage;Palaeofusulina: b. Changxingian Stage). Zhang insisted that the base of the Permian System should be placed at the base of (2)-a: Mapingian Stage, and it was reasonable to draw the boundary based on the evolutionary stage, i.e. the development of keriotheca, and this was suitable for establishing the biostratigraphic boundary. According to Zhang (1984), the most primitive fusulinacean with keriotheca is Montiparus, but he did not remark on Protriticites. The problems of the "Protriticites-type wall" still remain in question. The present zone's leading fossil belongs to Montiparus, and thus the zone is correlative with the Lower Permian Mapingian (Zhang, 1984), but the correlation based on the first appearanceof keriotheca is very difficult. Ross (1967, 1973) pointed out that the rapid evolution of fusulinaceans in the Eurasian Arctic province had produced a series of early schwagerinid genera such as Protriticites, Montiparus, Obsoletes and Triticites. Triticites was considered to be the only genus of this series which had successfully invaded in the mid-continent province. In short, the genera Obsoletes, Protriticites and Montiparus are representative of the Eurasian- Andean province and therefore the direct correlation based on these genera is very difficult among the other different faunal provinces. The present Montiparus sp. A Zone corresponds to the following biohorizons by Wilde (1984): Zone 2, Triticites planus, Eotriticites; Zone 3, Kansanella, Triticites ohioensis; Zone 4, Dunbarinella, Triticites beedei- moorei- plummeri, Waeringella, Rauserites}. In addition the following zones by Ross and Ross (1985b, 1987, 1988), probably correspond to the present zone: the Kansanella (Lowanella) winterensis and Triticites cf. ohioensis Zones; the Triticites ohioensis, Triticites collus, and Triticites nebraskensis Zones; the Triticites primarius and Kansanella neglecta Zones; the Triticites iatensis, Triticites newelli and Kansanella (Kansanella) joensis Zones; the Triticites mcgrewensis and Dunbarinella Zones of the southwestern United State. The Montiparus montiparus Zone and the Triticites acutus-Triticites quasiarcticus Zone ofRussia (Winkler, 1990), the upper part of the Montiparus montiparus Zone and the overlying Triticites acutus-Triticites quasiarcticus Zone of Russia (Popov et al., 1985; Chuvashov et al., 1986), the Montiparus montiparus Zone and the overlying Triticites acutus-Triticites ardicus Zone in Russia (Leven, 1980a, b, 1981; Leven and Shcherbovich, 1978) are also correlative with the present zone. The Triticites montiparus Zone in South China (Zhang et al., 1987) and the Montiparus range Zone or the Triticites acme Zone of Zhang (1983, 1991) are tentatively cor related with the present zone. 4. Triticites simplex Zone(s. 1.) The Triticites simplex Zone (s. 1.) comprises the tentatively discriminated two zones: the lower, the Schwagerina sp. A Zone, and the upper, the Triticites simplex Zone (s. s.). 4-(l). Schwagerina sp. A Zone This zone is characterized by the abundant occurrence of Schwagerina sp. A. The stratigraphic significance of the genus Schwagerina was mentioned by many Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 71 authors, for example, Dunbar and Skinner (1936), Dunbar (1958), Ross (1963b), Skinner and Wilde (1965) and Rauser and Shcherbovich (1970). In 1954, opinion 213 designated the type species of Schwagerina sensu Moller, 1877 with Borelis princeps Ehrenberg, 1842= Ehrenberg, 1854 sensu Dunbar and Skinner, 1936, non Schwagerina moelleri Rauser, 1937= Schwagerina princeps (Ehrenberg) sensu Moller, 1878. In Japan, many workers use the generic name Schwagerina sensu by Dunbar and Skinner (1936, 1937), but internationally, two types and senses for Schwagerina are apparently present. In short, two species of the Schwagerina are used for the type species, namely Schwagerina moelleri Rauser, 1936 = princeps (Ehrenberg, 1942) sensu Moller, 1878, and Schwagerina sensu Moller, 1877, based on the reexamination of Borelis princeps Ehrenberg by Dunbar and Skinner (1936). Wilde (1984) maintained that Rugosofusulina Rauser, 1938 is a synonym of Pseudofusulina Dunbar and Skinner, and numerous workers in C. I. S. had included Schwagerina in Pseudofusulina. Zhang (1991) noticed that the first appearance of Schwagerina was recognized at the base of the Triticites stuckenbergi Zone in Russia. Therefore, the present Schwagerina sp. A Zone is correlative with the lower part of the Triticites stuckenbergi Zone. Wilde (1984) correlated the Triticites-Schwagerina Zone with a part of Triticites (a part of C3b), Rauserites stuckenbergi (C3c), Jigulites (C3d) and Daixina (C3e). Sheng, Zhang and Wang (1988) regarded Daixina as a synonym of Schwagerina sensu Dunbar and Skinner, 1936. From these facts, the first appeared biohorizon ofSchwagerina probably corresponds to the base of'theDaixina fragilis Zone (Popov et al., 1985) and the Triticites stuckenbergi Zone in the other area. Rauser (1958) subdivided the Triticites arcticus-Triticites acutus Zone under the Triticites stuckenbergi Zone into five units as follows: (1) the Triticites irregularis-Fusiella granum- oryzae unit; (2) the Triticites acutus- Triticites rossicus unit; (3) the Rugosofusulina unit; (4) the Triticitesfortissimus unit, and (5) the Triticites praeexilis unit. Ofthem, the Triticites irregularis-Fusellagranum- oryzae unit contains Quasifusulina longissima (Moller). From the similarity between the obtained Quasifusulina sp. A and Quasifusulina longissima (Moller), the present Schwagerina sp. A Zone possibly corresponds to the upper Triticites arcticus-Triticites acutus Zone or the biohorizon over the latter zone. How ever, Quasifusulina sp. A has a more advanced form than Quasifusulina longissima (Moller), and the first appearance of Schwagerina seems to coincide with the lower boundary of the Triticites siuckenbergi Zone. Taking this evidence into consideration, the Schwagerina sp. A Zone probably corresponds to the Triticites stuckenbergi Zone in other areas, or Zone 5, the lower part ofthe Triticites-Schwagerina Zone (Wilde, 1984), or the Triticites callosus, Triticites cullomensis and Triticites plummeri Zones (Ross and Ross, 1985b, 1987, 1988). 4-(2). Triticites simplex Zone (s. s.) This zone is characterized by the following fusulinaceans (M. Ota, 1977): Triticites simplex (Schellwien), Triticites ozawai Toriyama, Triticites montiparus (Ehren berg, 1854) sensu Moller, 1878, non Ehrenberg: Fusulina montipara (Moller, 1878) 72 Yasuhiro Ota sensu Ozawa, 1925, Triticites biconicus Toriyama, Triticites suzukii (Ozawa), Triticites noinskyi paula Toriyama, Triticites arctica (Schellwien), Quasifusulina longissima (Mol ler) and Schubertella kingi Dunbar and Skinner. The diagnostic species, Triticites simplex (Schellwien) was not found along AK Traverse and thus this zone was divided by the other diagnostic fusulinaceans. In this paper, the Triticites simplex Zone by M. Ota (1977) is divided into three zones, namely, the lower, the Montiparus sp. A Zone, the middle, the Schwagerina sp. A Zone, and the upper, the Triticites simplex Zone (s. s.). The Montiparus sp. A Zone probably corresponds to the stratigraphically lower biohorizon, bearing Triticites montiparus sensu Ozawa and Quasifusu lina longissima (Moller). The Schwagerina sp. A Zone is correlated with the biohorizon of Triticites biconicus Toriyama. The Triticites simplex Zone (s. s.) corres ponds to the biohorizonof Triticites ozawai Toriyama. Therefore, the Triticites simplex Zone (s. s.) in this paper is correlated with the upper part of the Triticites simplex Zone (M. Ota, 1977), a part of the Triticites-Schwagerina Zone, the upper of Zone 5, and 6 (Wilde, 1984), and the Triticites subventricosus, Triticites whetstonensis, Schubertella whetensis Zones, and the Leptotriticites americana, Triticites ventricosus, Schwagerina cf. Schwagerina longissimoidea Zones (Ross and Ross, 1985b, 1987, 1988). 5. Pseudoschwagerina muongthensis Zone The datum level of this zone is well defined by the first occurrence of the inflated schwagerinid, Pseudoschwagerina. This zone is characterized by Pseudoschwagerina muongthensis (Deprat) and the base coincides with the biohorizon bearing Pseudo schwagerina morikawai Igo. Hence, this biohorizon is correlated with that of the in flated schwagerinids. Inflated schwagerinids have been studied by many paleontologists for a long time. The following important studies on inflated schwagerinids should be men tioned: Dunbar and Skinner (1936, 1937), Dunbar (1958), Rauser (1959, 1960), M. -Maklay (1959), Ross (1962, 1963a, b, 1964, 1967, 1972a, 1973, 1982), Tikhvinskiy (1965), Rauser and Shcherbovich (1958, 1970), Sheng, Wang and Zhong (1984), Davydov (1984), Leven (1987) and Yang and Hao (1991). Dunbar and Skinner (1936) defined Schwagerina and established two new genera, namely, Pseudoschwagerina and Paraschwagerina. Then, they designated Schwagerina uddeni Beede and Kniker, 1924, as the type species of Pseudoschwagerina and remarked that the proloculus of this genus is commonly large, and the whorls of thejuvenarium are relatively short and thickly fusiform (pi. 11, figs. 6 and 7). Original designation of Schwagerina uddeni Beede and Kniker included both microspheric and megalospheric forms. Dunbar and Skinner (1936, plate 11, figs. 6-7; 1937, plate 50, figs. 1-10; 1937, plate 53, fig. 8) regarded a typical form ofPseudoschwagerina uddeni (Beede and Kniker, 1924) sensu Dunbar and Skinner as a megalospheric form, but Schwagerina uddeni Beede and Kniker, 1924 originally includes the microspheric form also. In their description, Dunbar and Skinner (1936) expressed as "commonly large" for the proloculus, and they implicitly recognized the existence of the microspheric form. Such being the Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 73

case, it is preferable that Pseudoschwagerina has both the two types microspheric and megalospheric forms. Furthermore, the holotype of Pseudoschwagerina was designated by Thompson (1948) with the specimen figured by Beede and Kniker (pi. 6, fig. 1, axial section of microspheric form). M. -Maklay (1959) classified Schwagerinidae Dunbar and Henbest, 1930 into 10 genera, recognizing Schwagerina Moller, 1877 and establishing new genera, namely Occidentoschwagerina and Sphaeroschwagerina (in 1956, Sphaeroschwagerina was originally proposed by M. -Maklay, but no description was done.). Rauser and Shcherbovich (1958) recognized both Pseudoschwagerina Dunbar and Skinner, 1936 and Schwagerina Moller, 1877. Rauser (1959) treated Pseudoschwagerina Dunbar and Skinner, 1936 as distinct from Schwagerina Moller, 1877 based on the form of each juvenarium. Rauser (1960) subdivided Schwagerina Moller, 1878 into five genera, and Zellia Kahler, 1937 into three groups. In addition, she established the new genus Parazellia with Fusulina muongthensis Depart, 1951 (pi. II, fig. 1) as the type species. Rauser and Fursenko (1959) also regarded Schwagerina Moller, 1877 as an independent genus and designated Schwagerina princeps sensu Moller, 1878 as the type species. Rauser and Shcherbovich (1970) discussed characters of Schwagerina Moller, 1877 and they clearly distinguished Pseudoschwagerina Dunbar and Skinner from Schwagerina Moller. As mentioned before the type species of Schwagerina sensu Moller, 1877 is Borelis princeps Ehrenberg, 1842 without doubt. If Schwagerina moelleri Rauser, 1936 and Schwagerina moelleri Rauser, 1949 are distinguishable from Schwagerina uddeni Beede and Kniker, 1924, a new genus will be established for Schwagerina "moelleri" Rauser. Perhaps, the concept of the above new genus corresponds to that of Alpinoschwagerina Bensh, 1972. However, Alpinoschwagerina Bensh, 1972 is considered to be a synonym of Pseudoschwagerina Dunbar and Skinner, 1936. Sheng, Zhang and Wang (1988) distinguished Sphaeroschwagerina M. -Maklay, 1959 from Pseudoschwagerina Dunbar and Skinner, 1936 by its having concave pointed poles and small proloculus. However, they treated Alpinoschwagerina Bensh as a synonym of Sphaeroschwagerina M. -Maklay, 1959. In addition, they emphasized that Schwagerina in Russia is the same as Pseudoschwagerina Dunbar and Skinner. According to Loeblich and Tappan (1988), Sphaeroschwagerina can be distinguished from Pseudoschwagerina by its short axis. To the contrary, Alpinoschwagerina, which was established by its having a much smaller proloculus than that of Pseudoschwagerina, practically cannot be distinguished from Pseudoschwagerina Dunbar and Skinner, 1936. In a word, Alpinoschwagerina rep resents the microspheric form of Pseudoschwagerina. On the other hand, Davydov (1984) studied the origin of "Schwagerina" and discussed two lineages, Biwaella?- Dutkevichites- Sphaeroschwagerina and Biwaella?- Biwaella. Then he proposed the sub family Biwaellinae, and mentioned that the taxonomic homonym between "Schwager ina" and Pseudoschwagerina still continues. Moreover, he pointed out that the overestimated "Schwagerina sensu Rauser" should be treated as Sphaeroschwagerina, which was applied to the inflated "Schwagerina" of M. -Maklay (1959). Leven 74 Yasuhiro Ota

(1987) noticed that among the group of "Schwagerina", Occidentoschwagerina, Para schwagerina, Pseudoschwagerina and Zellia appeared in Asselian time, whereas Robusto schwagerina in Sakmarian time, and Orientoschwagerina appeared in Murgabian time. Additionally, he mentioned about the origin of Schubertellidae Skinner, 1931 and agreed with the Davydov's opinion in 1984, in which schubertellid was regarded as an ancestor of Biwaella. Davydov (1988b) regarded the occurrence of Schwagerina sensu Davydov (1988b) as being at the lower horizon of the Daixina (Ultradaixina) postsokensis Zone. As a result, the collected megalospheric species at AK 26 along AK Traverse was discriminated as Pseudoschwagerina muongthensis (Deprat) because it has a relative ly large proloculus, thick spirotheca and inflated outline. Loeblich and Tappan (1988) and Sheng, Zhang and Wang (1988) also regarded it as Pseudoschwagerina. In the AK area, the collected inflated schwagerinids with microspheric proloculus are closely similar to a variation of Pseudoschwagerina morikawai Igo, 1957. Judging from the morphology of Pseudoschwagerina, the collected specimen was identifiable as Pseudoschwagerina morikawai Igo. The present Pseudoschwagerina muongthensis Zone is approximately correlated with the biozone between the first occurrence of inflated schwagerinids and the occurrence of typical Pseudofusulina in other areas. 5. Pseudofusulina vulgaris Zone The characteristic speciesof this zone is Pseudofusulina vulgaris s. s. (Schellwien, 1909). Internationally, several variations of Pseudofusulina are present. Naoumova and Rauser (1964) reported two different types of Pseudofusulina at different stratigra phic positions. Rauser (1951) reported a primitive type of "Pseudofusulina" fauna from the "Pseudofusulina Horizon" (C3II) under the Schwagerina Horizon (C3III). According to this, Pseudofusulina ex. gr. vulgaris Schellwien, 1908, occurs from an older horizon than the Schwagerina Horizon. Davydov (1988a, b), reexamined pseudofusulinids and discussed their origin. Zhang (1983, 1991) made the bioho rizon of the first appearance of the "Pseudofusulina" coincide with the lower boundary of the Daixina sokensis Zone. If this is so, Pseudofusulina appears under the Pseudo schwagerina Zone. Pseudofusulina was first established by Dunbar and Skinner (1931) with Pseudofusulina huecoensis Dunbar and Skinner, 1931 as the type species. Pseudo fusulina, at one time, was regarded as a synonym of Schwagerina (Dunbar and Skin ner, 1936). Rauser (1937) proposed the new genus Rugosofusulina with Alveoli prisca Ehrenberg em. Moeller as the type species. Thompson (1948) designated the holotype of Pseudofusulina huecoensis (plate 1, figure 5, Dunbar and Skinner, 1931). Rauser (1949) studied Pseudofusulina Dunbar and Skinner, 1931 and referred Fusulina moelleri Schellwien, 1908 to Pseudofusulina. Since then, the confusion be tween Pseudofusulina and "Schwagerina" has continued. Skinner and Wilde (1965, 1966) revised the definition of the genus Pseudofusulina, because of the existence of rugosity in Pseudofusulina huecoensis Dunbar and Skinner, 1931. At the same time, they established the new genus Chalaroschwagerina characterized by having a distinct Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 75 phrenothecae. Rozovskaya (1975) treated Rugosofusulina Rauser, 1937 as a valid genus, but did not recognized Chalaroschwagerina Skinner and Wilde, 1965 because the latter genus was treated as a synonym of Pseudofusulina Dunbar and Skinner. Thompson (1964) accepted both Pseudofusulina Dunbar and Skinner and Rugosofusu lina Rauser. In Loeblich and Tappan (1988) Rugosofusulina Rauser was treated as a synonym of Pseudofusulina Dunbar and Skinner, but Chalaroschwagerina Skinner and Wilde, 1965 was treated as valid. Sheng, Zhang and Wang (1988) also recognized both Pseudofusulina and Chalaroschwagerina as distinct genera. They additionally commented that Chalaroschwagerina has a special form which is distinct from the genus Pseudofusulina. They also pointed out that the sense of Pseudofusulina in Russia was a mixed one of Schwagerina sensu Dunbar and Skinner (1936) and Pseudofusulina sensu Dunbar and Skinner (1931). Consequently, the stratigraphic position and defini tion of "Pseudofusulina" are ambiguous and its correlation is very difficult at present. According to Leven (1970), the following species are the index fusulinaceans of Upper Artinskian time: Misellina (Brevaxina) dyhrenfurtki (Dutk.), Darvasites ordinatus (Chen), Darvasites contractus (Schellw. and Dyhr.), Rugosofusulina vulgariformis Kalm., Pseudofusulina kraffti (Schellw. and Dyhr.) and Pseudofusulina fusiformis (Schellw. and Dyhr.), Pseudofusulina exigua (Schellw. and Dyhr.). Thus, the upper limit of the present Pseudofusulina vulgaris Zone becomes older than the base of the Upper Artinskian. Leven (1975) insisted that the Sakmarian Stage with robustoschwager- inids and paraschwagerinids must be assigned to the deposits in the interval between the lower, the Schwagerina Bed and the upper, the Pseudofusulina Bed with Pseudofusuli na vulgaris-Pseudofusulina kraffti. Leven (1979) proposed that the Bolorian Stage is divided into the upper, the Misellina parvicostata Zone and the lower, the Misellina dyhrenfurtki Zone. He mentioned that the Bolorian species, comparing with their immediate ancestors, have larger dimensions, and more intense and regular folding of septa and cuniculus. Furthermore, he concluded that the characteristic fusulina ceans of the Pseudofusulina vulgaris Zone, the Pseudofusulina fusiformis Zone, and the Pseudofusulina ambigua Zone (Kanmera and Mikami, 1965a, b), the Pseudofusulina ambigua Zone of Toriyama (1958) and the Pseudofusulina kraffti magna Zone, renamed by Hasegawa (1963), were similar to those which accompanied misellinids in Darvaz, and further more that the Parafusulina kaerimizensis Subzone with misellinids (Nogami, 1961) is probably correlated with the Upper Kubergandian Stage. Leven (1980b) correlated the Yakhtashian Stage, named after Mt. Yakhtash in Darvaz with the Pseudofusulina vulgaris Subzone (Toriyama, 1958). Leven and Shcherbovich (1980) pointed out that Pseudofusulina vulgaris (Deprat) is a primitive species regarded as Chalaroschwagerina. From these facts and studies, the present Pseudofusulina vulgaris Zone probably corresponds to the lower part of the "Chalaroschwagerina" vulgaris Zone or the biohorizon under the latter zone (Leven and Shcherbovich, 1978), and the Pseudofusulina vulgaris-Laxifusulina iniqua Zone (Zhou et al. 1987), the Pseudoschwagerina convexa, Pseudofusulina nelsoni, Schwagerina diversiformis, and Eoparafusulina Zones (Ross 76 Yasuhiro Ota and Ross, 1985b, 1987, 1988).

-II-4. Conclusion The investigated AK area was selected in front of the Akiyoshi-dai Museum of Natural History, southern part of the Akiyoshi Plateaus (s. s.). Materials from 56 localities were collected along AK Traverse. 15 genera and 44 species of fusulinaceans were described. Limestones on AK Traverse are mainly composed of alternating beds with sparry calcite cements and micritic or micrite matrices, and are intercalated with the black to dark brown colored limestones. These limestones yield abundant fusulinaceans and algae, and interbedded with them are rather coarse limestones containing fragments of crinoids and bryozoans. From these studies, the following six zones including tentatively discriminated four zones in a narrow sense are recognized along AK Traverse: 1. Pseudofusulinella hidaensis Zone, 2. Protriticites matsumotoi Zone (s. 1.), 2-(l). Protriticites matsumotoi Zone (s. s.), 2-(2). Quasifusulinoides sp. A Zone, 3. Montiparus sp. A Zone, 4. Triticites simplex Zone (s. 1.), 4-(l). Schwagerina sp. A Zone, 4-(2). Triticites simplex Zone (s. s.), 5. Pseudoschwagerina muongthensis Zone, 6. Pseudofusulina vulgaris Zone. The distribution of these zones indicates that the limestones in this area have a general northeastern strike and the younger zones are successively distributed toward the northwest. Furthermore, the limestones along AK Traverse are recognizableas the alternations of limestone of two different sequences, probably caused by a fault of NE-SW trend (Ozawa and Kobayashi, 1990). In addition, the tentatively discriminated Quasifusulinoides sp. A Zone was not identified in the second sequence. The lower part of the overlying Montiparus sp. A Zone is composed of limestones with sparry calcite cements containing characteristic fusulinaceans similar to those of the underlying zone, namely Protriticites matsumotoi (Kanmera). The transitions from Fusulininae or Fusulinellinae to Schwagerininae are also recognizable between the Quasifusulinoides sp. A Zone or the Protriticites matsumotoi Zone (s. s.) and the Montiparus sp. A Zone. Thus, gaps might be present between the underlying Protriticites matsumotoi Zone (s. 1.) and the overlying Montiparus sp. A Zone. However, these gaps are interpreted as of small scale, because genus level transitions between zones shift gradually as mentioned above. The recognized fusulinacean zones were attempted to be corre lated with the biostratigraphic zones in the reference sections. The inflated schwagerinids have a worldwide distribution and are very useful for international correlation of the Upper Carboniferous to Lower Permian. On AK Traverse, the Pseudoschwagerina muongthensis Zone was characterized by the occurrence of Pseudos chwagerina muongthensis (Depart) and the base of this zone was defined by the first occurrence of Pseudoschwagerina morikawai Igo. The author tentatively made the basal boundary coincide with the first occurrence of pseudoschwagerinids in other

areas. Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 77

-III-l. The third investigated area, Mt. Maruyama, Mine City, Yamaguchi Prefecture The third investigated area, Mt. Maruyama, is located in Mine City, Yamaguchi Prefecture. In this chapter, the author would like to discuss the phylogenetic consideration of the species relative to Protriticites yanagidai Ota and Protriticites masamichii Ota from the Mt. Maruyama area.

,200m- Fusulinella simplicata Subzone / (Kyuma and Nishida, 1987)

Fusulinella biconica Subzone (Kyuma and Nishida, 1987) Yr-~-> Profusulinella beppensisZone

_170rn /

Fig. 26. Distribution of fusulinacean zones in the third investigated area, Mt. Maruyama with a locality, MA 66. 78 Yasuhiro Ota

The Mt. Maruyama area is underlain by Middle to Upper Carboniferous limestones, and these limestones generally have a northeast strike and a northward dip. Furthermore, limestones of this area are regarded as reef facies deposits and contain stromatolites and chaetetids (M. Ota, 1968). According to Kyuma and Nishida (1987), the following zones are distributed in ascending order: the Profusu linella beppensis Zone, the Fusulinella simplicata Subzone and the Fusulinella biconica Subzone (Fig. 26). The author measured the section along the traverse, namely MA Traverse to clarify the localities of the collected fusulinids. Locality MA 66 yields the following species: Protriticitesyanagidai Ota, Protriticites masamichii Ota, Protriticites toriyamai Ota and Protriticites aff. matsumotoi (Kanmera) mainly obtained from limestones with sparry calcite cements. Limestones of the Mt. Maruyama area are composed of biomicrite to biomicru- dite, bryozoa-crinoid biosparite, and shell-crinoid biosparrudite. New species of goniatites were described in this area (Kyuma and Nishida, 1987). These sedimen tary features suggest that the limestones in this area were formed in a paleoenviron ment similar to the reef core in the Akiyoshi organic reef complex. Limestones near Loc. MA 66 seem to have accumulated on a reeffiat of a bypass margin between the fore reef and open sea, because they yield fragments of ammonoids and fusulinaceans (Y. Ota, 1994).

Form ratio

2.00 .

1.00 4.00

Length (mm) Fig.27. Each form ratio of the length to width. K: Protriticites afT. matsumotoi. M: Protriticites masamichii. T: Protriticites toriyamai. Y: Protriticites yanagidai. Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 79

-III-2. Phylogenetic Consideration The collected species, Protriticites yanagidai Ota, Protriticites masamichii Ota, Protriticites toriyamai Ota and Protriticites aff. matsumotoi (Kanmera), are characterized by their small size, compared to the known species ofProtriticites. Each form ratio of the length to widthis shown in Fig. 27. Of these species, Protriticites toriyamai has the smallest size shell. Protriticites yanagidai and Protriticites masamichii are almost the same in size. Protriticites aff. matsumotoi is about twice as large as Protriticites yanagidai or Protriticites masamichii. Protriticitesyanagidai Ota has a small, fusiform to ellipsoidal shell, with slightly and irregularly convex lateral slopes and somewhat sharply pointed poles. The present species is closely similar to Protriticites globulus Putrya, as the type species of the genus Protriticites. Furthermore, it resembles Protriticites matsumotoi, which was first described as Triticites (s. 1.) by Kanmera (1955). There fore the phylogenetic line from Protriticites yanagidai Ota to Protriticites matsumotoi (Kanmera) is similar to the primitive species of Triticites (s. 1.). On the other hand, Protriticites masamichii Ota resembles Montiparus matsumotoi infktus, reported by Watanabe (1991) in having moderately inflated, oval to subspherical shell. Furthermore, this species is similar to the illustration of Montiparus montiparus shown by Rozovskaya (1950). Here, Protriticites masamichii Ota and Montiparus matsumotoi infktus of Watanabe (1991) are probably linked together with a phylogenetic line (Fig. 28). From these viewpoints, Protriticites yanagidai is considered to be in a primitive stage of the phylogenetic lines towards Protriticites matsumotoi, while Protriti cites masamichii seems to be a transitional species to Montiparus matsumotoi inflatus. In the investigatedJigoku-dani area, the limestones bearing Protriticites masamichii in the Protriticites toriyamai Subzone are successively overlain by limestones with Protriticites matsumotoi (Kanmera) in the Protriticites matsumotoi Subzone. From this field evidence and the morphological affinities, Protriticites matsumotoi is considered to be derived possibly from the primitive species of Protriticites, namely Protriticites tori yamai, Protriticites masamichii and Protriticitesyanagidai. On the other hand, limestones of the Protriticites matsumotoi Subzone are successively overlain by limestones with Montiparus sp. A in the Montiparus sp. A Zone at the Jigoku-dani area. In the AK area, the Protriticites matsumotoi Zone (s. s.) are overlain by the Montiparus sp. A Zone with small gaps, but the limestones are in nearly complete succession. Montiparus sp. A is closely similar to Montiparus matsumotoi inflatus of Watanabe (1991). Therefore, Montiparus sp. A and Montiparus matsumotoi infktus sensu Watanabe are possibly derived from the primitive species of Protriticites, but it is uncertain whether Protriticites matsumotoi is directly connected with above species of Montiparus. Incidentally, Montiparus matsumotoi inflatus of Watanabe (1991) was mainly reported from the Omi Limestone, whereas Protriticites matsumotoi is from the Yayamadake Limestone. The above speciations and phyletic transitions might have resulted from the geographic isolation between the Akiyoshi Limestone, the Yayamadake and Omi Limestones. However, the Akiyoshi Limestone yields these fusulinaceans as mentioned above and 80 Yasuhiro Ota

Yayamadake Geographic Speciation ? Omi

or Chronologic speciation 7

Fig. 28. Phylogenetic consideration. 1. Protriticites yanagidai Y'. Ota. 2. Protriticites globulus Putrya. 3. Protriticites matsumotoi (Kanmera). 4. Protriticites masamichii Y. Ota. 5, 7. Montiparus matsumotoi inflatus, reported from Watanabe (1991). 6. Montiparus montiparus from Rozovskaya (1950). 8. Obsoletes obsoletus (Schellwien). nearly complete successions of limestones from the Protriticites Zone to the Montiparus Zone are confirmed without a remarkable hiatus. Hence, the above speciations and phyletic transitions have a great possibility to be the result of chronological speciation. Furthermore, the collected species from the Mt. Maruyama area have close affinities with Protriticites praemontiparus Zhou, Sheng and Wang, 1987 and Protriticites minor Zhou, Sheng and Wang, 1987 from eastern Yunnan, South China. The fusulinaceans in the Akiyoshi organic reef complex probably are closely related to those of South China during this period. Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 81

Consideration

The purpose of this study is to reexamine the Middle Carboniferous to the Lower Permian fusulinacean biostratigraphic units in the Akiyoshi Limestone Group. The details are shown in the previous chapters. Here the author would like to summarize the paleontology of the Jigoku-dani, AK and Mt. Maruyama areas, which respectively contain the characteristic fusulinacean fauna, reflecting slight differences of paleoenvironmental character. Jigoku-dani area, AK area in front of Akiyoshi-dai Museum of Natural History, and Mt. Maruyama area were selected and the field investigations were carried out. First investigated area, Jigoku-dani is located in the northwestern part of the Akiyoshi Plateau (s. s.). The inverted limestones of Middle Carboniferous to the Lower Permian are widely distributed in this area. The studies in this area, lead to the following conclusions: The collected materials from the measured sections, JI Traverse comprise 56 fusulinacean species including two subspecies and 23 genera. From the fusulinacean constituents and distinctions of lithofacies, limestones were tentatively divided into nine zones including seven subzones from the Middle Carboniferous to the Lower Permian. These zones are well traceable in this area. They are as follows: 1. Fusulinella biconica Zone; 2. Fusulina cf. shikokuensis Zone, 2-1. Fusulinella cf. obesa Subzone, 2-2. Pseudofusulinella hidaensis Subzone; 3. Obsoletes obsoletus Zone, 3-1. Protriticites toriyamai Subzone, 3-2. Protriticites matsumotoi Subzone; 4. Montiparus sp. A Zone; 5. Triticites yayamadakensis Zone, 5-1. Triticites saurini Subzone, 5-2. Schwagerina sp. A Subzone, 5-3. Triticites biconicus Subzone; 6. Schwagerina (?) cf. satoi Zone; 7. Pseudoschwagerina muongthensis Zone; 8. Pseudofusulina vulgaris globosa Zone; 9. Pseudofusulina aff. ambigua Zone. Distribution of these zones indicates that limestones are inverted in structure. They are composed mainly of micritic limestones without frame building organisms. The limestone facies suggest that they were deposited in a relatively low energy environment like a lagoon within the Akiyoshi organic reef complex. Furthermore, they were successively accumu lated without a remarkable hiatus, because no remarkable faunal break could be observed in the limestone sequence. Considerable facies changes are present near the basal boundaries of the Schwagerina (?) cf. satoi Zone and the Pseudoschwagerina muongthensis Zone. Limestones near the basal boundary of the Schwagerina (?) cf. satoi Zone intercalate fairly coarse grainstones with fragments of reef frame builders and the fusulinacean diversity becomes larger across the boundary. Limestones near the base of the Pseudoschwagerina muongthensis Zone consist of rather coarse grainstones with the sparry calcite cement. In this paper, the author tentatively correlates the limestones of the Jigoku-dani area with Middle Carboniferous to Lower Permian strata in other areas of Japan and outside Japan by using the first occurrence of the inflated schwagerinids, i.e. Pseudoschwagerina. The inflated schwagerinids are very useful to correlate the Upper Carboniferous and the Lower Permian, because they are 82 Yasuhiro Ota widely distributed in many regions andare assumed to be planktonic during a part of their life cycle. They seem to be excellent index fossils for the correlation of the Upper Carboniferous to the Lower Permian. However, they are also known to occur in distinctive facies, such as biohermal limestones. Therefore, for regional correla tion, examination of the associated fossils along with the inflated schwagerinids is indispensable. The second investigated AK area is located in front of the Akiyoshi-dai Museum of Natural History. AK Traverse was measured and fossils collected along the traverse. From the paleontological and lithological viewpoints, the following fusu linacean zones are tentatively discriminated in ascending order: Pseudofusulinella hidaensis Zone, Protriticites matsumotoi Zone (s. s.), Quasifusulinoides sp. A Zone, Montiparus sp. A Zone, Schwagerina sp. A Zone, Triticites simplex Zone (s. s.), Pseudoschwagerina muongthensis Zone and Pseudofusulina vulgaris Zone. Detailed field mapping of the area revealed two limestone sequences cut by a fault of northeastern trend in this area. Limestones appear to have accumulated in a marginal lagoon environment in the Akiyoshi organic reef complex. The Mt. Maruyama area in Mine City, Yamaguchi Prefecture, is the third investigated area. The limestone facies of this area indicate that the paleoenviron ment is probably a true reef within the organic reef complex. Loc. MA 66 was examined in detail and the following fusulinaceans were identified: Protriticites yanagidai Ota, Protriticites masamichii Ota, Protriticites toriyamai Ota and Protriticites aff. matsumotoi (Kanmera). These species are characterized by having rather small shell, as compared with the known species of Protriticites. From their morphological characters, two phylogenetic lines were shown among the primitive Triticites (s. 1.). The first line is from Protriticites yanagidai Ota to Protriticites matsumotoi (Kanmera). The second one is from Protriticites masamichii Ota to Montiparus matsumotoi infktus, reported by Watanabe (1991). From hypothesis based on the morphological affinities, Protriticites yanagidai seems to be a primitive stage in the first line, whereas Protriticites masamichii is considered to be a transitional species in the second line. The transition from Protriticites masamichii to Protriticites matsumotoi in association with Protriticites toriyamai is successively confirmed in the Protriticites toriyamai Subzone to the Protriticites matsumotoi Subzone in the Jigoku-dani area. Therefore, Protriticites matsumotoi (Kanmera) seems to be linked to the above primitive species of Protriticites. Furthermore, the Montiparus sp. A Zone, though small gaps were present, conform ably overlies the Protriticites matsumotoi Subzone or Zone along AK and JI Traverses. Therefore, the relevant species of Montiparus sp. A and Montiparus matsumotoi infktusof Watanabe (1991) are probably linked to the primitive species of Protriticites, but it is doubtful whether Protriticites matsumotoi (Kanmera) is directly connected with Monti parus matsumotoi infktus sensu Watanabe, because of its morphological characters. In addition these fusulinaceans are closely similar to Protriticites praemontiparus Zhou, Sheng and Wang, 1987 and Protriticites minor Zhou, Sheng and Wang, 1987, Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 83 respectively from eastern Yunnan, South China. The examinations of the fusulina cean affinities between China and Japan are very important for studying paleobiogeography during Carboniferous-Permian time. The tentative divisions of the fusulinacean zones proposed for the Middle Carboniferous and Lower Permian Akiyoshi Limestone Group and the relevant sections are shown in Fig. 17. As mentioned before, it is very difficult to obtain a consensus on the leading and index fusulinaceans of each zone even in the Akiyoshi Limestone. This seems to be caused mainly by the differences of the original habitats and the fusulinacean ecological adaptations and has a close relationship with the paleoecology in the Akiyoshi organic reefcomplex (e.g. M. Ota, 1968; Nagai and M. Ota 1980; Nagai, 1985). M. Ota (1977) already mentioned that habitat segregation is observable with the fusulinacean distribution in the Akiyoshi Lime stone, namely Pseudofusulina kraffti magna Toriyama in the lagoonal facies and Pseudofusulina ambigua (Deprat) in the sand facies of the reef flat environment. The following paleoecology studies were well known before. Ross (1961, 1965, 1969, 1972b) tried to establish biostratigraphic zones, by considering their paleoen vironment. He remarked that fusulinaceans lived on the surface of the substratum and have adapted to the influence of water conditions, such as temperature, salinity, currents and turbidity. Ross (1964) suggested that the morphological changes were due to ecological adaptation, for example, the inflated schwagerinids occur in specific rock types, such as patch reef accumulations or bioherms. Tikhvinskiy (1965) insisted that the elongated and fusiform genera of Schwagerininae were undoubtedly bottom dwellers, but some genera with inflated form probably had a planktonic habit. Menner (1971) criticized the above opinions because it was very difficult to confirm whether the genus "Schwagerina" is planktonic or benthonic. Ross (1972b) reconstructed the isolated bioherms in the lower Wolfcampian Neal Ranch Forma tion, and discussed the fusulinacean habitats. According to him, the inflated schwagerinids, including Pseudoschwagerina uddeni (Beede and Kniker), have a distribution near the biohermal buildups and on associated debris aprons. More over, Ross (1982) insisted that some genera in the inflated schwagerinids had a planktonic phase in the life cycle. Ross and Ross (1988) and Seslavinskiy (1991) made it clear that during late Carboniferous and early Permian time, transgression shifted to regression. Furthermore, Ross and Ross (1988) suggested that the sedimentary environment from the base to upper part of the Wolfcampian changes from shelf to basin. Sea level changes may closely relate to the worldwide dispersal of the inflated schwagerinids. The sedimentary environments of the Akiyoshi Limestone Group in the investi gated AK Traverse were, as a whole, reconstructed as like a marginal lagoon within the Akiyoshi organic reef complex. The Jigoku-dani area is recognizable as a relatively low energy environment like a lagoon. The Mt. Maruyama area, on the contrary, reveals an environment near the reef core, according to the biofacies and 84 Yasuhiro Ota

lithofacies. Along AK Traverse, well preserved Pseudoschwagerina were obtained from micritic limestone. The collected specimens of Pseudoschwagerina from AK Traverse, are considered to be preserved in the original living position and form. Machiyama and Kawamura (personal communication), examined the biohorizon of Pseudoschwagerina along AK Traverse and concluded that the energy level of that environment was very low because of abundant occurrence of wackestone. In contrast with the AK area, Pseudoschwagerina in theJigoku-dai area rarely occurs in limestones with sparry calcite cements and is poorly preservation. Under high energy condition, Pseudoschwagerina seems to be difficult to preserve well, because of its thin and not very strong walls. Pseudoschwagerina in the Akiyoshi organic reef complex probably chose its habitat in the marginal lagoon environment and sometimes extended into the central environ ment of the lagoon. The Triticites-Schwagerina Zone (s. s.) outside the Akiyoshi region, approximately corresponds to the Triticites yayamadakensis Zone and the Triticites simplex Zone along AK and JI Traverses. These zones in the investigated areas are typified by dominance of Triticites (s. s.) and are also characterized by abundance of Schwagerina sp. A along two traverses. Triticites yayamadakensis Kanmera is abundant and easily traced in the Jigoku-dani area, but this species is rare along AK Traverse. Triticites ozawai Toriyama, a closely related species to Triticites yayamadakensis Kanmera occurs along AK Traverse. Fusulinacean constituents of these zones along AK and JI Traverses are slightly different, but the above zones also yield many mutual fusulinaceans. The Montiparus sp. A Zone is confirmedin both AK and Jigoku-dani areas. The lower part of the Montiparus sp. A Zone along AK Traverse is accompanied by the underlying diagnostic Protriticites matsumotoi (Kanmera). This species might be regarded as a member of a "ghost fauna" or the mixed fauna derived from various zones, resulting from condensation by sea level changes. Hence, gaps are possibly present between the overlying Montiparus sp. A Zone and the underlying Quasifusuli noides sp. A Zone in the Protriticites matsumotoi Zone (s. 1.). Furthermore, the horizon of the gaps coincides with the biohorizon, changing from Fusulininae or Fusulinell inae to Schwagerininae. Consequently the geological event, suggested by the gaps, is considered to play an important role in the transition from Fusulininae or Fusulinellinae to Schwagerininae. However, Ross (1989) has already pointed out that the time for fusulinacean transitions in such a condensed section is too short to be reason for the evolution of fusulinaceans. Therefore, the rapid transitions from Fusulininae or Fusulinellinae to Schwagerininae observed along AK Traverse are dependent on the original evolutionary cause, which fusulinaceans possess rather than that caused by paleoenvironmental change. Hasegawa (1963, 1988) discussed the origin of the black sparry calcite limestone near the boundary between the Carboniferous and Permian. According to him, the datum level of the lower limits Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 85

of the black sparry calcite limestone coincides with the biohorizon, where the Fusulina-Fusulinella fauna extinguishes, and the new Triticites (s. 1.) fauna appears. From its chemical composition, this black to dark brown color limestone is not dolomitic, and changes of sedimentary environments are suggested (Musashino, Hikabe and Arai, personal communication). It is possible that the black to dark brown color limestone along AK Traverse is the product of a geological event, that took place after the limestone accumulations of the Quasifusulinoides sp. A Zone. The Protriticites matsumotoi Zone in the investigated areas was first introduced by M. Ota (1977) as the Triticites (s. 1.) matsumotoi Zone, and is characterized by primitive species of Triticites (s. 1.), such as Protriticites matsumotoi (Kanmera). In connection with this zone, Minato, Kato, Nakamura, Niikawa and Hasegawa (1984) reported that Protriticites matsumotoi (Kanmera) was widely found in Southwest Japan. Hasegawa (1988) also reported that the Triticites simplex fauna partly overlies in occurrence the rather primitive Triticites (s. 1.) fauna, such as Protriticites matsumotoi fauna. He assumed that the primitive Triticites (s. 1.) was probably able to settle only in the area, where conditions suitable for fusulinacean recovery arrived early in the environmental change. Of the study areas, AK Traverse and JI Traverse are supposed to be the presumably recovered areas for them, because a rather primitive Triticites (s. 1.) fauna, such as Protriticites matsumotoi fauna, was found. The Fusulina-Fusulinella Zone, comparable with the Beedeina akiyoshiensis Zone of M. Ota (1977) was not confirmed along AK Traverse and in the Jigoku-dani area. Beedeina akiyoshiensis (Toriyama) is known in limestones with sparry calcite cements, accumulated in a reef environment. Therefore, it is suggested that Beedeina akiyoshiensis (Toriyama) originally could not live in a relatively low energy environ ment like along AK and JI Traverses, where the central to marginal lagoon environment was predominant. As mentioned above, in the Akiyoshi Limestone Group the Middle Carbonifer ous and Lower Permian fusulinaceans of each zone are slightly different in their com position in different areas. This fact suggests that some fusulinaceans have distinc tive habitats different from others in the Akiyoshi organic reef complex. These distributional characters control the local bio-divisions and fusulinacean zonations. Hence, the analysis of the fusulinacean assemblages, relating to their special distribution habitat in the Akiyoshi organic reefcomplex, is essential to establish the detailed biostratigraphic division in the future. The establishment ofdetailed biostratigraphic units is very important for making clear the process of formation of the Akiyoshi organic reefcomplex and is essential to learning the paleogeography of Japan in late Paleozoic time. In this connection, Hill (1973) referred to the relation between the sedimentary environment of the organic reef and the paleolatitude. In fact, Japanese Islands in late Paleozoic time was formerly illustrated in many paleogeographic maps nearly at the north latitudeof 60° in the Arctic region (e.g. Smith et al. 1973; Boucot and Gray, 1980). Taking 86 Yasuhiro Ota the Akiyoshi organic reef complex (e.g. M. Ota, 1968; Nagai, 1978, 1979; Sugiyama and Nagai, 1990) and modern coral reef into consideration, the above location of the late Paleozoic Japanese Islands, including Akiyoshi region, is unsuitable with present knowledge. Ross and Ross (1985a) and Scotese and Mckerrow (1990) showed the location of the Japanese Islands in late Paleozoic time near the equator. Their conclusions agree with the results of the present study. With regard to the changes of fusulinacean genera along AK and JI Traverses, the following generic transitions are confirmed: Pseudofusulinella- Protriticites- Montiparus- Triticites (Schwagerina)- Pseudoschwagerina- Pseudofusulina. The genus Pseudofusulinella was first introduced by Thompson (1951) and is considered to have originated from Fusulinella, in the Eurasian Arctic faunas at about the end of late Carboniferous time (Ross, 1973). According to Rui, Ross and Nassichuk (1991), the Tethyan province, namely tropical and subtropical climatic zones, is marked by the transitional series of Fusulinella-Neostaffella-Beedeina-Fusulina fauna. Therefore, during the period of the Pseudofusulinella Zone, corresponding to the Fusulina and Beedeina Zones, the Akiyoshi organic reef complex was formed in a subtropical and tropical environment rather than just an area with a warm temperature. Addi tionally, the faunal transition from the Protriticites Zone to the Montiparus Zone was confirmed along AK and JI Traverses. As respects Triticites (s. 1.), many authors, for examples, Davydov (1990) and Ginkel and Villa (1991) have discussed it before. The successive transition from Protriticites to Montiparus has been confirmed in the Tethyan province but not in the Mid-continent province. Hence, the Tethyan faunal province during the time from the Protriticites matsumotoi Zone to the Montiparus sp. A Zone seems to have little connection with that of the Mid-continent faunal province. The Pseudoschwagerina muongthensis Zoneis characterized by the widespread genus, Pseudoschwagerina. This genus is considered to be planktonic during a part of its life cycle. In a strict sense, the development of the Pseudoschwagerina muongthensis fauna in the Akiyoshi Limestone Group possibly has a time lag in comparison with that of Pseudoschwagerina uddeni (Beede and Kniker) in the Mid-continental province, because the pseudoschwagerine faunas arose in western NorthAmerica and after that they dispersed and migrated into the Tethys ocean. However, this dispersal time was short and we can adapt synchronism to the migration rapidity of Pseudoschwager ina. This is the reason why Pseudoschwagerina is very useful for worldwide correlation. The next overlying Pseudofusulina Zone is characterized by a cosmopolitan genus, Pseudofusulina. However, the stratigraphic distribution and definition of this zone are still left in question.

Acknowledgments The author expresses his grateful thanks to Professor Juichi Yanagida, Kyushu University, who kindly read the manuscript and offered many helpful suggestions to Fusulinacean Biostratigraphyof the Akiyoshi Limestone Group, Part I 87

accomplish this study. Cordial thanks are due to Professor Hakuyu Okada and Associate Professor Akihiko Matsukuma, Kyushu University, for reading the manuscript and their giving the author helpful criticisms and suggestions during the course of this study. The author also wishes to express his grateful thanks to Professor Kimiyoshi Sada, Hiroshima University, who kindly read the manuscript and provided many suggestions about fusulinaceans. Dr. Kametoshi Kanmera, Professor Emeritus, Kyushu University gave him many valuable comments and helpful suggestions on the fusulinacean paleontology. Dr. Wilbert R. Danner, Professor Emeritus, University of British Columbia, kindly read the manuscript and made minor changes in grammar and syntax where needed, and provided useful comments and suggestions. Dr. Masamichi Ota, Director of the Kitakyushu Museum and Institute of Natural History critically read the manuscript and offered many valuable comments and helpful suggestions. The author thanks the following persons for their kind help in giving him facilities in field work and valuable suggestions; Professor Tamio Nishida, Saga University, Assoc. Prof. Koichi Nagai, Ryukyu University, Assoc. Prof. Testuo Sugiyama, Fukuoka University, Dr. Kyoichiro Ueda, Curator of the Kitakyushu Museum and Institute of Natural History, Messrs. Akihiro Sugimura and Takehiko Haikawa, Akiyoshi-dai Museum of Natural History and Mrs. Yuko Kyuma, Primary School of Nagasaki Prefecture.

References

Beede, J. W. and H. T. Kniker. 1924. Species of the genus Schwagerina and their stratigraphic significance. Texas Univ. Bull., (2433): 1-97, pis. 1-9. Boucot, A. J. and J. Gray. 1980. A Cambro-Permian pangaeic model consistent lithofacies and biogeographic data. In Strangway, D. W. (ed.), The continental crust and its mineral deposits, Geol. Assoc. Can. Spec. Pap. 20, pp. 389-419. Chen Tszin'-shi. 1963. K morfologii i sistematike rodov Protriticites, Quasifusulinoides i Obsoletes iz progranichnykh otlozheniy srednego i verkhnego karbona. Voprosy Mikropaleont., 7: 71-84, pis. 1-6. Chuvashov, B. I., E. Y. Leven and V. I. Davydov. 1986. Pogrnichnye odozheniy karbona i permi Urala, Priural'ya i Sredney Azii (Biostratigrafiya i korrelyatsiya). Izd. Nauk, Moskva: 1-152,pis. 1-32. Davydov,V. I. 1984. K voprosu o proiskhozhdenii shchvagerin. Paleont. Zhurnal, (4): 3-16, pi. 1. Davydov, V. I. 1988a. About a phylogenetic criterion of weighing specific features in foraminifer systematics (exemplified by fusulinids). Benthos' 86, Revue de Paleobiologie. Geneve, Museum d'Histoire Naturelle, Vol. spec. No.2, Partie, I: 47-55. Davydov, V. I. 1988b. O proiskhozhdenii i razvitii nekotorykh "psevdofuzulin". Paleont. Zhurnal, (3): 10-21. Davydov, V. I. 1990. K utochneniyu proiskhozhdcniya i filogenii trititsitesov i granitsysrednego i verkhnego otdelov karbona. Paleont. Zhurnal, (2): 13-25. Deprat, J. 1913. Les Fusulinides des Calcaircs Carboniferiens et Permiens du Tonkin, du Laos et du Nord-Annam. Mem. Serv. Geol. de I'Indochine, 2, Fasc. 1, £tude des Fusulinides de Chine et d'Indochine II. Mem.: 1-74, pis. 1-10. 88 Yasuhiro Ota

Ding Yunjie, Xia Guoying, Li Li, Yu Xueguang, Zhao Songyin and Zhao Zhen. 1991. The Carboniferous-Permian boundary and faunas from Xikou area, Zhen' an, Shaanxi in eastern Qinling range. Bull. Tianjin Inst., Geol. Min. Resour., Chinese Acad. Geol. Sci., Geol. Publ. House, Beijing, China, (24): 1-202, pis. 1-31. Dunbar, C. O. 1958. Paleontological notes. Jour. Paleontology, 32(5): 1019-1030. Dunbar, C. O., Permian Subcommittee of the National Research Council's Committee on Stratigra phy. 1960. Correlation of the Permian formations of North America. Bull. Geol. Soc. America, 71: 1763-1806. Dunbar, C. O. and J. W. Skinner. 1931. New fusulinid genera from the Permian of West Texas. American Jour. Sci., 22: 252-268, pis. 1-3. Dunbar, C. O. and J. W. Skinner. 1936. Schwagerina versus Pseudoschwagerina and Paraschwagerina. Jour. Paleontology, 10(2): 83-91, pis. 10-11. Dunbar, C. O. and J. W. Skinner. 1937. The geology of Texas. Volume III. Part 2. Permian Fusulinidae ofTexas. Texas Univ. Bull., (3701): 517-825, pis. 42-81. Dunham, R. J. 1962. Classification of carbonate roks according to depositional texture. In Ham, W. E. (ed.), Classification ofcarbonate rocks, A. A. P. G., Mem., 1, pp 108-121, pis. 1-7. Eto, J. 1967. A lithofacies analysis of the lower portion of the Akiyoshi Limestone Group. Bull. Akiyoshi-dai Sci. Mus., (4): 7-42, pis. 1-5. Fomichev, V. D. 1960. O granitse kamennougol'noy i permskoy sistem i ob artemovskom komplekse otlozheniy. Sovetskaya Geologiya, (11): 94-108. Fujii, A. 1972. Ota Formation of the Yamaguchi Group in the Akiyoshi district, four. Geol. Soc. Japan, 78(6): 309-321. Fujii, A. and T. Mikami. 1970. Tsunemori Formation - its relation with Akiyoshi limestone. Jour. Geol. Soc. Japan, 76(11): 545-557, pi. 1. Fujimoto, H. 1959. Recent studies of the Paleozoic group ofJapan. Jour. Geol. Soc. Japan, 65(766): 406-411. Ginkel, A. C. and E. Villa 1991. Some fusulinids from the Moscovian • Kasimovian transition in the Carboniferous of the Cantabrian mountains (NW Spain). Proc. Kon. Ned. Akad. v. Wetensch., 94(3): 299-359. Gobbett, D. J. 1973. Permian fusulinacea. In Hallam, A. (ed.), Atlas of palaeobiogeography, pp. 151-158, Elsevier Scientific Publishing Company, Amsterdam, London, New York. Haikawa, T. 1986. Lower Carboniferous of the Okubo area in the Akiyoshi limestone plateau, Southwest Japan. Bull. Akiyoshi-dai Mus. Nat. Hist., (21): 1-35, pis. 1-7. Haikawa, T. 1988. The basement complex and conodonts biostratigraphy of the lower parts in the Akiyoshi Limestone Group, Southwest Japan. Bull. Akiyoshi-dai Mus. Nat. Hist., (23): 13-37, pis. 4-7. Haikawa, T. and M. Ota. 1978. A Lower Carboniferous Coral Reef found in the Nagatophyllum satoi Zone of the Akiyoshi Limestone Group, Southwest Japan. Bull. Akiyoshi-dai Mus. Nat. Hist., (13): 1-14, pis. 1-8. Haikawa, T. and M. Ota. 1983. Restudy of the Nagatophyllum satoiOzawa and Carcinophyllum enorme (Ozawa) from the Akiyoshi Limestone Group, Southwest Japan. Bull. Akiyoshi-dai Mus. Nat. Hist., (18): 35-52, pis. 1-5. Hanzawa, S. 1942. The stratigraphical relation between the Carboniferous and Permian formations in Manchuria, Korea and Japan proper. Japanese Jour. Geol. Geogr., 18(3): 97-108. Hasegawa, Y. 1958. Note on the geological structure of the Akiyoshi Plateau, S. W. Honshu. Chikyu Kagaku (Earth Science; Journal of the Association for the Geological Collaboration in Japan), (39): 15-18. Hasegawa, Y. 1963. New find of fossils in the reddish tuffaceous shale in the Akiyoshi province. Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 89

Chikyu Kagaku (Earth Science; Journal of the Association for the Geological Collaboration in Japan), (64): 32-37. Hasegawa, Y. 1967. Profusulinella daiyamensis n. sp. from the Profusulinella Zone of the Akiyoshi Limestone Group. Sci. Rep., Niigata Univ., Ser. E, Geology andMineralogy, (1): 9-15, pis. 1-3. Hasegawa, Y. 1988. "Faunal transition and the stratigraphy near the Carboniferous and Permian boundary in the inner zone of the southeast Japan". Reports of Kakenhi: 1-14, pis. 1-3. Hashimoto, K. 1979. Bio- and litho-facies of the Akiyoshi Limestone Group in the southern area of the Akiyoshi Plateau. Bull. Akiyoshi-dai Mus. Nat. Hist., (14): 1-26, pis. 1-12. Hayasaka, I. and M. Minato. 1954. The Paleozoic ofJapan. Proc., I. G. C. 19th Session, Alger, Sec. 13: 193-204. Hill, D. 1973. Lower Carboniferous corals. In Hallam, A. (ed.), Atlas ofpalaeobiogeography, pp. 133-142, Elsevier Scientific Publishing Company, Amsterdam, London, New York. Ichikawa, K. 1984. Tectonic development ofthe basement structure of Eastern Asia I. In Huzita, K. (ed.), Tectonic Beltsof Asia, pp. 223-238, Kaibundo, Tokyo. Ichikawa, K. 1990. Pre-Cretaceous terranes ofJapan. In Ichikawa, K. etal. (eds.) Pre-Cretaceous terranes of Japan, pp. 1-12, Publication of IGCP Project No. 224: Pre-Jurassic Evolution of Eastern Asia, Osaka. Igo, H. 1957. Fusulinids of Fukuji, southeastern part of the Hida Massif, central Japan. Tokyo Kyoiku Daigaku, Sc. Rep., Sec. C, 5(47): 153-246, pis. 1-15. Ishii, K. 1990. Provinciality of some fusulinacean faunas of Japan. In Ichikawa, K. et al. (eds.) Pre-Cretaceous terranes ofJapan, pp. 297-305, Publication of IGCP Project No. 224, Pre-Jurassic Evolution of Eastern Asia, Osaka. Kahler, F. 1961. Ungenauigkeiten der Karbon-Permgrenze im Bereich der fusuliniden-fazies. N. Jahrbuchf. Geologie u. Palaonlologie. Monatshefte: 113-124. Kanmera, K. 1952. The Upper Carboniferous and the Lower Permian of the Hikawa Valley, Kumamoto, Pref., Kyushu, Japan. Jour. Geol. Soc. Japan, 58(676): 17-32. Kanmera, K. 1955. Fusulinids from the Yayamadake limestone of the Hikawa Valley, Kumamoto Prefecture, Kyushu, Japan. Part II. Fusulinids of the Upper Carboniferous. Japanese Jour. Geol. Geogr., 26(3-4): 177-192, pis. 11-12. Kanmera, K. 1958. Fusulinids from the Yayamadake limestone of the Hikawa Valley, Kumamoto Prefecture, Kyushu, Japan. Part III. Fusulinids of the Lower Permian. Mem. Fac. Sci., Kyushu Univ., Ser. D, Geology, 6(3): 153-215, pis. 24-35. Kanmera, K. and T. Mikami. 1965a. Succession and sedimentary features of the Lower Permian Sakamotozawa Formation. Mem. Fac. Sci., Kyushu Univ., Ser. D, Geology, 16(3): 265-274. Kanmera, K. and T. Mikami. 1965b. Fusuline zonation of the Lower Permian Sakamotozawa Series. Mem. Fac. Sci. Kyushu Univ., Ser. D, Geology, 16(3): 275-320, pis. 44-53. Kanmera, K. and H. Nishi. 1983. Accreted oceanic reef complex in Southwest Japan. In Hashimoto, M. and S. Uyeda (eds.), Accretion tectonics in the circum-paciflc regions, pp. 195-206, Terra Scientific Publishing Company, Tokyo. Kanmera, K., K. Ishii and R. Toriyama. 1976. The evolution and extinction patterns of Permian fusulinaceans. In Kobayashi, T. and W. Hashimoto (eds.), Contributions to the Geology and Palaeontology ofSoutheast Asia, 17, pp. 129-154, Univ. Tokyo Press,Japan. Kanuma, M. 1953. On some Moscovian fusulinids from southern part of Hida platean, Gifu Pref., Japan. Bull. Tokyo Gakugei Univ., Ser. Mathematics, Geology and Physics, 4: 23-33, pi. 3. Kawano, M. 1960. Stratigraphy of the Paleozoic formation and some considerations on their facies in Yamaguchi Prefecture. Bull. Fac. Educ. Yamaguchi Univ., 9, Part 2: 43-62. Kimura, T., I. Hayami and S. Yoshida. (eds.). 1991. Geology ofJapan, 287 pp., Univ. Tokyo Press, Japan. 90 Yasuhiro Ota

Kobayashi, T. 1935. The geologic structure of southwestern Japan and its Mesozoic Palaeogeogra- phy. Jour. Geol. Soc. Japan, 42(500): 228-584. Kobayashi, T. 1941. The Sakawa orogenic cycle and its bearing on the origin of the Japanese Islands. Jour. Fac. Sci., Imp. Univ. Tokyo, Sec. II, Geology, Mineralogy, Geography, Seismology, 5, Part 7: 219-578, pis. 1-4. Kyuma, Y. and T. Nishida. 1987. Akiyoshiceras, a new neoicoceratid ammonoid genus from the Upper Carboniferous of Akiyoshi (Molluscan Paleontology of the Akiyoshi Limestone Group- VII). Bull. Akiyoshi-dai Mus. Nat. Hist., (22): 23-41, pis. 1-5. Lapkin, I. Yu. and Yu. I. Kats. 1990. Geologicheskiye sobytiya na rubezhe karbona i permi. Izvest. Akad. Nauk SSSR, Ser. Geol., (8): 45-58. Leven, E. Y. 1970. O proiskhozhdenii vysshikh fuzulinid. Paleont. Zhurnal, (3): 18-25, pi. 1. Leven, E. Y. 1975. Yarusnaya shkala permskikh otlozheniy Tetisa. Byull. Moskov. Ob. Ispytateley. Prirody, Old. Geol., 5(1): 5-21. Leven, E. Y. 1979. Bolorskiy yarus permi: obosnovaniye, kharakteristika, korrelyatsiya. Izvest. Akad. Nauk SSSR, Ser. Geol., (1): 53-65. Leven, E. Y. 1980a. Ob"yasintel'naya zaplska k stratigraficheskoy shkale permskikh odozheniy oblasti Tetis. Vsesoyuznyy Ordena Lenina Nauchno-Issledovalel'skii, Geologicheskii Institut (VSEGEI): 1-51. Leven, E. Y. 1980b. Yakhtashskiy yarus permi: obosnovaniye, kharakteristika, korrelyatsiya. Izvest. Akad. Nauk SSSR, Ser. Geol., (8): 50-60. Leven, E. Y. 1981. Permian Tethys stage scale and correlation of sections of the Mediterranean Alpine folded belt. IGCP No. 5, Newsletter, 3: 100-112. Leven, E. Y. 1987. Sistema i filogeniya semeystva Schubertellidae Skinner, 1931. Paleont. Zhurnal, (2): 30-40, pis. 2-3. Leven, E. Y. and S. F. Shcherbovich. 1978. Fuzulinidy i stratigrafiya assel'skogo yarusa Darvaza. Izd. Akad. Nauk, SSSR, Moskva: 5-162, pis. 1-21. Leven, E. Y. and S. F. Shcherbovich. 1980. Kompleks fuzulinid sakmarskogo yarusa Darvaza. Voprosy Mikropaleont., 23: 71-85. Loeblich, A. R., Jr. and H. Tappan. 1988. Foraminiferal genera andtheir classification, 970 pp., separate volume, pis. 1-847. Van Nostrand Reinhold Company Inc., New York. Matsusue, K. 1986. Foraminiferal biostratigraphy of the lower part of the Akiyoshi Limestone Group. Sci. Repts.,Dept. Geol., Kyushu Univ., 14(4): 163-185, pis. 2-7. Matsusue, K. 1988. Some aberrant fusulinaceans from the Upper Carboniferous sequence of the Akiyoshi Limestone Group, Southwest Japan. Trans. Proc. Palaeont. Soc. Japan, N. S., (152): 644- 653. Menner, V. V. (1971): Prostranstvcnnoye znachcniye stratigraficheskikh podrazdeleniy. Byull. Moskov. Ob. Ispytateley Prirody, Otdel Geol., (2): 9-16. Miklukho-Maklay, A. D. 1959. Znachenic gomeomorfii dlya sistematiki fuzulinid. Uchenye Zapiski Leningrad. Gosudarstvennogo Univ., Ser. Geol. Nauk, 10(268): 155-172. Miklukho-Maklay, A. D. 1963. Verkhniy palaeozqy Sredney Azii, 329 pp., Izd. Leningrad Univ. Miklukho-Maklay, A. D., D. M. Rauser-Chernousova and S. E. Rozovskaya. 1958. Sistematika i filogeniya fuzulinidey. Voprosy Mikropaleont., 2: 5-21. Minato, M., M. Kato, K. Nakamura, I. Niikawa and Y. Hasegawa. 1984. Carboniferous- Permian boundary in Japan. Neuvieme Congres International de Stratigraphic et de Geologic du Carbonifere, Compte Rendu, 2: 587-592. Miura, Y. 1987. Mineralogical study of Akiyoshi Kaerimizu limestone-(I). Bull. Akiyoshi-dai Mus. Nat. Hist., (22): 1-22. Murata, M. 1961. On the geological structure of Akiyoshi Plateau. Tohoku Univ., Inst. Geol. Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 91

Paleont., Contr., (53): 1-46. Nagai, K. 1978. Litho- and Bio- facies of reef limestones in the Ryugoho area of the Akiyoshi limestone plateau. Bull. Akiyoshi-dai Mus. Nat. Hist., (13): 15-34, pis. 9-16. Nagai, K. 1979. "Reef limestones in the lower part of the Akiyoshi Limestone Group". The Earth Monthly (Chikyu), 1(9): 661-667. Nagai, K. 1985. Reef-forming algal chaetetid boundstone found in the Akiyoshi Limestone Group, Southwest Japan. (Reconstruction of the "Akiyoshi Organic Reef"-I). Bull. Akiyoshi-dai Mus. Nat. Hist., (20): 1-15, pis. 1-6. Nagai, K. and M. Ota. 1980. On the geology of the Minami-dai area of the Akiyoshi limestone plateau, Yamaguchi Prefecture. Part 1: Biostratigraphy and geologic structure. Reports Earth Sci., College Gen. Education, Kyushu Univ., (21): 7-15. Nakamura, M. and M. Ota. 1974. On some Carboniferous dasycladacean plants from the Akiyoshi Limestone Group at Nishiyama area, Akiyoshi, Southwest Japan. Bull. Akiyoshi-dai Sci. Mus., (10): 9-15, pis. 3-5. Naoumova, S. and D. M. Rauser-Chernousova. 1964. Sur la position stratigraphiquc de l'Autunien et de ses analogues. Cinquieme Congres International de Stratigraphie et de Geologic du Carbonifere, Compte Rendu: 1215-1227, pis. 1-4. Nikitina, A. P. 1969. Pervye predstaviteli Obsoletes, Protriticites i Fusulina iz verkhnego karbona Primorskogo kraya. Paleont. Zhurnal, (4): 3-11, pis. 1-2. Nishida, T. 1971. Carboniferous ammonoids from Akiyoshi (Molluscan paleontology of the Akiyoshi Limestone Group-IV). Bull. Akiyoshi-dai Sci. Mus., (7): 1-24, pis. 1-7. Nishida, T. and Y. Kyuma. 1982. Mid-Carboniferous ammonoids from the Akiyoshi Limestone Group (Molluscan paleontology of the Akiyoshi Limestone Group-V). Bull. Akiyoshi-dai Mus. Nat. Hist., (17): 1-54, pis. 1-10. Nishida, T. and Y. Kyuma. 1984. Notes on Pseudoparalegoceras from the Akiyoshi Limestone Group (Molluscan paleontology of the Akiyoshi Limestone Group-VI). Jour. Fac. Edu. Saga Univ., 31(2), Part II: 221-241, pis. 1-3. Nogami, Y. 1961. Permische fusuliniden aus dem Atetsu-plateau siidwestjapans. Teil 2. Ver- beekininae, Neoschwagerininae u. a. Mem. Coll. Sci., Univ. Kyoto, Ser. B, Geology and Mineralogy, 28(2): 159-228, pis. 1-7. Okimura, Y. 1987. Taishaku limestone - Its sedimentary environments and invertebrate fossils. "Taishaku no shizen" ("Nature in Taishaku"): 59-75, pis. 5-7. Ota, M. 1968. The Akiyoshi Limestone Group: A geosynclinal organic reef complex. Bull. Akiyoshi-dai Sci. Mus., (5): 1-44, pis. 1-31. Ota, M. 1971. Faunas and correlation of the "Uzura" quarry limestone of the Akiyoshi, Southwest Japan. Part II. Fusulininan fauna. Bull. Akiyoshi-dai Sci. Mus., (7): 65-74, pis. 12-13. Ota, M. 1977. Geological studies of Akiyoshi. Part I. Generalgeologyof the Akiyoshi Limestone Group. Bull. Akiyoshi-dai Sci. Mus., (12): 1-33, pis. 1-3. Ota, M., R. Toriyama, A. Sugimura and T. Haikawa. 1973. Restudy on the geologic structure of the Akiyoshi Limestone Group. Jour. Geol. Soc. Japan, 82(3): 115-135. Ota, N., A. Sugimura and M. Ota. 1969. Reef deposits in the Millerella Zone of the Akiyoshi Limestone Group. Palaeont. Soc. Japan, Spec. Pap., (14): 1-12, pis. 1-3. Ota, Y. 1994. Upper Carboniferous fusulinids from Mt. Maruyama, Mine City, Yamaguchi Prefecture. Bull. Kitakyushu Mus. Nat. His., (13): 1-35, pis. 1-3. Ota, Y. and M. Ota. 1993. Faunal change of the Upper Carboniferous to Lower Permian fusulinaceans from the Akiyoshi Limestone Group, Southwest Japan. Bull. Akiyoshi-dai Mus. Nat. Hut., (28): 1-57, pis. 1-3. Ozawa, T. 1967. Pseudofusulinella, a genus of Fusulinacea. Trans. Proc. Palaeont. Soc. Japan, N. S., 92 Yasuhiro Ota

(68): 149-173, pis. 14-15. Ozawa, T. and F. Kobayashi. 1990. Carboniferous to Permian Akiyoshi Limestone Group. Benthos'90, The Fourth International Symposium on Benthic Foraminifera, Sendai, Japan, Guidebook for Field Trip No.4: 1-31, pis. 1-13. Ozawa, T. and F. Kobayashi and K. Watanabe. 1990. Biostratigraphic zonation of Late Carboniferous to Early Permian sequence of the Akiyoshi Limestone Group, Japan and its correlation with reference sections in the Tethyan region. Spec. Pub., Saito Ho-on Kai, (3): 327- 341. Ozawa, Y. 1923. Stratigraphical study on the so-called Upper Chichibu System (Palaeozoic) with the Akiyoshi Limestone. Jour. Geol. Soc. Japan, 30(357): 227-243. Ozawa, Y. 1925. Paleontological and stratigraphical studies on the Permo-Carboniferous limestone of Nagato. Part II. Paleontology. Jour. Coll. Sci., Imp. Univ. Tokyo, 45, Art. 6: 1-90, pis. 1- 14. Popov, A. P., V. I. Davydov,, L. M. Donakova and O. L. Kossovaya. 1985. K stratigrafii gzhel'skogo yarusa Yuzhnogo Urala. Sovetskaya Geologiya, (3): 57-67. Putrya, F. S. 1948. Protriticites-novy rod fuzulinid. Trudy L'vovskogo Geologicheskogo Obshchestva pri Gosudarstvennom Universitete im. lvana Franko, Paleontologicheskaya Seriya, 1: 89-96, pi. 1. Rauser-Chernousova, D. M. 1937. Rugosofusulina-novyy rod fuzulinid. Etyduy po Mikropaleontologiy, Paleontologicheskaya Laboratoriya Moskovskogo Gosudarstvennogo Universiteta, Moskva, 1: 9-26, pis. 1-3. Rauser-Chernousova, D. M. 1949. Nekotorye psevdofuzuliny i parafuzuliny Bashkirskogo Priural'ya. Akad. Nauk SSSR, Trudy Inst. Geol. Nauk, Geol. Ser., 105(35): 118-162, pis. 1-11. Rauser-Chernousova, D. M. 1951. Fatsii verkhnekamcnnougolnykh i artinskikh otlozhenii Sterlitamaksko-Ishimbaiskogo Priuralya (Na osnove izucheniya fuzulinid). Akad. Nauk SSSR, Trudy Inst. Geol. Nauk, Geol. Ser., 119(43): 108 pp. Rauser-Chernousova, D. M. 1958. Opyt sverkhdrobnogo raschleneniya razreza verkhne- kamennougol'nykh otlozheniy v rayonc kuybyshevskoy ges. Akad. Nauk SSSR, Trudy Geologiches kogo Instituta, 13: 121-138, pis. 1-2. Rauser-Chernousova, D. M. 1959. Sur I'ontogenese chez les Fusulinids (Foraminiferes). Bulletin de la Societe Geologique de France, 7e se'rie, tome 1: 658-661. Rauser-Chernousova, D. M. 1960. Reviziya shvagerin s blizkimi rodami i granitsa karbona i permi. Voprosy Mikropaleont., 4: 3-32. Rauser-Chernousova, D. M. 1965. Etapnost' i periodichnost' v istoricheskom razvitii fuzulinid. Dokl. Akad. Nauk SSSR, 160(4): 914-917. Rauser-Chernousova, D. M. and A. V. Fursenko (eds.). 1959. Osnovy Paleontologii, Obshchaya chast', Prosteyshie. 482 pp., Izd. Akad. Nauk SSSR, Moskva. Rauser-Chernousova, D. M. and A. K. Shchegolve. 1979. The Carboniferous-Permian boundary in the USSR. In Wager, R. H. et al. (eds.), The Carboniferous of the U. S. S. R., Yorkshire Geological Society, Occasional Publication, (4), pp. 175-191. Rauser-Chernousova, D. M. and S. F. Shcherbovich. 1958. O shvagerinovom gorizonte tsensral'noy chasti Russkoy platformy. Akad. Nauk SSSR, Trudy Geolgoicheskogo Instituta, 13: 3- 53, pis. 1-6. Rauser-Chernousova, D. M. and S. F. Shcherbovich. 1970. O morfologii predstaviteley roda Schwagerina Moller, 1877 sensu Moller, 1878 i terminologii ikh priznakov. Voprosy Mikro paleont., 13: 30-51, pis. 3-8. Rauser-Chernousova, D. M. and S. F. Shcherbovich. 1974. Nekotorye voprosy kasimovskogo yarusa v svstc izucheniya fuzulinid. Izvest. Akad. Nauk SSSR, Ser. Geol., (6): 91-103. Ross, C. A. 1961. Fusulinids as palcoccological indicators. Jour. Paleontology, 35(2): 403-404. Ross, C. A. 1962. The evolution and dispersal of the Permian fusulinid genera Pseudoschwagerina and Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 93

Paraschwagerina. Evolution, 16(3): 306-315. Ross, C. A. 1963a. Early Permian fusulinids from Macusani, southern Peru. Palaeontology, 5, Part 4:817-823, pi. 119. Ross, C. A. 1963b. Standard Wolfcampian Series (Permian), Glass Mountains, Texas. Geol. Soc. Am. Mem. 88: 1-205, pis. 2-29. Ross, C. A. 1964. Evolutionof the inflatedSchwagerinidae. Proc,I. G. C.22th Session, India, Sec. 8: 351-364. Ross, C. A. 1965. Late Pennsylvanian Fusulinidae from the Gaptank Formation, West Texas. Jour. Paleontology, 39(6): 1151-1176, pis. 141-145. Ross, C. A. 1967. Development of fusulinid (Foraminiferida) faunal realms. Jour. Paleontology, 41(6): 1341-1354. Ross,C. A. 1969. Paleoecology of Triticites and Dunbarinella in Upper Pennsylvanian strata ofTexas. Jour. Paleontology, 43(2): 298-311. Ross, C. A. 1972a. Paleobiological analysis of fusulinacean (Foraminiferida) shell morphology. Jour. Paleontology, 46(5): 719-728. Ross, C. A. 1972b. Paleoecology fusulinaceans. Proc. I. G. C, 23th Session, Czechoslovakia, Sec. 4: 301-318. Ross, C. A. 1973. Carboniferous Foraminiferida. In Hallam, A. (ed.), Atlas of palaeobiogeography, pp. 127-132, Elsevier Scientific Publishing Company, Amsterdam, London, New York. Ross, C. A. 1982. Paleobiology of fusulinaceans. Third North American Paleontological Convention, Proceedings, 2: 441-445. Ross, C. A. 1984. Fusulinacean biostratigraphy near the Carboniferous-Permian boundary in North America. Neuvieme Congres International deStratigraphie et de Geologic du Carbonifere, Compte Rendu, 2: 535-542. Ross, C. A. 1989. Basal Permian biostratigraphy, discussion and proposal. In Wardlaw, B. R. (ed.), Proceeding at the 28th International Geological Congress, pp. 2-5, Working Group on the Carboniferous-Permian boundary. Ross, C. A. and J. R. P. Ross. 1985a. Carboniferous and Early Permian biogeography. Geology, 13: 27-30. Ross, C. A. and J. R. P. Ross. 1985b. Late Paleozoic depositional sequences are synchronous and worldwide. Geology, 13: 194-197. Ross, C. A. and J. R. P. Ross. 1987. Biostratigraphic zonation of late Paleozoic depositional sequences. In Ross, C. A. and D. Haman (eds.), Timing and Depositional History of Eustatic Sequences: Constraints on Seismic Stratigraphy, Cushman Foundation for Foraminiferal Resarch, Spec. Publ. 24, pp. 151-168. Ross, C. A. and J. R. P. Ross. 1988. Late Paleozoic transgressive-regressive deposition. In Wilgus, C. K. et al. (eds.), Sea-level changes: an integrated approach, SEPM, Spec. Pub.42, pp. 227-247. Rozovskaya, S. E. 1948. Klassifikatsiya i sistematicheskie priznaki roda Triticites. Dokl. Akad. Nauk SSSR, 59(9): 1635-1638. Rozovskaya, S. E. 1950. Rod Triticites, ego razvitie i stratigraficheskoe znachenie. Trudy Paleont. Inst., Akad. Nauk SSSR, 26: 1-80, pis. 1-10. Rozovskaya, S. E. 1975. Sostav, sistcma i filogeniya otryada Fuzulinida. Trudy Paleont. Inst.,Akad. NaukSSSR, 149: 1-267, pis. 1-35. Rui Lin, C. A. Ross and W. W. Nassichuk. 1991. Upper Moscovian (Desmoinesian) fusulinaceans from the type section of the Nansen Formation, Ellesmere Island, Arctic Archipelago. Geol. Surv. Can. Bull., (418): 1-72, pis. 1-24. Rui Lin. and Zhang Linxin. 1987. Carboniferous-Permian boundary in the world. In C. Wang (ed.), Carboniferous boundary in China, pp. 163-180, Contribution to the 11th International 94 Yasuhiro Ota

Congress of Carboniferous Stratigraphy and Geology, 1987, Beijing, China. Sada, K. and T. Yokoyama. 1970. Fusulinids of the Fusulinella Zone of the Taishaku Limestone. Mem. Fac. Gen. Ed., Hiroshima Univ. Ill, 4: 39-44, pi. 1. Sakagami, S. 1964a. Bryozoa of Akiyoshi, Part 1. Permian Bryozoa from the Shigeyasu quarry. Bull. Akiyoshi-dai Sci. Mus., (3): 1-24, pis. 1-8. Sakagami, S. 1964b. Bryozoa of Akiyoshi, Part 2. LowerCarboniferous Bryozoa from the Uzura quarry. Trans. Proc. Palaeont. Soc. Japan, N. S., (56): 295-308, pis.44-45. Sakagami, S. and A. Sugimura. 1978. Morozovapora, a new Carboniferous bryozoan genus from the Akiyoshi Limestone, Japan. Proc. Japan, Acad., Ser. B, 54(6): 257-261. Sakagami, S. and A. Sugimura. 1983. Three interesting Carboniferous bryozoans from the Akiyoshi Limestone Group, Japan. Proc. Japan Acad., Ser. B, 59(3): 39-42. Sano, H., Y. Iijima and H. Hattori. 1987. Stratigraphy of the Paleozoic rocks in the Akiyoshi Terrane of the central Chugoku massif. Jour. Geol. Soc. Japan, 93(12): 865-880. Sano, H. and K. Kanmera. 1988. Paleogeographic reconstruction of accreted oceanic rocks, Akiyoshi, Southwest Japan. Geology, 16: 600-603. Sano, H. and K. Kanmera. 1991a. Collapse of ancient oceanic reef complex- What happened during collision of Akiyoshi reefcomplex?-Geologic setting and age of Akiyoshi terrane rocks on western Akiyoshi-dai plateau. Jour. Geol. Soc. Japan, 97(2): 113-133, pi. 1. Sano, H. and K. Kanmera. 1991b. Collapse of ancient oceanic reef complex- What happened duringcollision of Akiyoshi reefcomplex?-Broken limestone ascollapse products. Jour. Geol. Soc. Japan, 97(3): 217-229, pis. 1-6. Sano,H. and K. Kanmera. 1991c. Collapse of ancient oceanic reefcomplex-What happened during collision of Akiyoshi reef compIex?-Limestone breccias, redeposited limestone debris and mudstone injections. Jour. Geol. Soc. Japan, 97(4): 297-309, pis. 1-6. Sano, H. and K. Kanmera. 1991d. Collapse of ancient oceanic reefcomplex-What happened during collision of Akiyoshi reef complexP-Sequence of collisional collapse and generation of collapse products. Jour. Geol. Soc. Japan, 97(8): 631-644, pis. 1-3. Schellwien, E. and G. Dyhrenfurth. 1909. Die asiatischen Fusulinen. A. Die Fusulinen von Darwas. Palaeontographica, 56: 137-176, pis. 13-16. Schwan, W. and M. Ota. 1977. Geological studies of Akiyoshi. Part II. Structural tectonics of the Akiyoshi Limestone Group and its surroundings, Southwest Japan. Bull. Akiyoshi-dai Sci. Mus., (12): 35-110. Scotese, C. R. and W. S. Mckerrow. 1990. Revised world maps and introduction. In Mckerrow W. S. and C. R. Scotese (eds.), Palaeozoic Paiaeogeography and Biogeography, Geol. Soc. Mem., (12), pp. 1-21. Seslavinskiy, K. B. 1991. GlobaPnyye transgressii i regressii v paleozoye. Izvest. Akad. Nauk SSSR, Ser. Geol., (1): 71-79. Sheng Jin-zhang, Wang Yu-jing and Zhong Bi-zhen. 1984. Some species of the genus Robusto schwagerina from eastern Yunnan. Acta Palaeont. Sinica, 23(5): 523-531, pis. 1-3. Sheng Jin-zhang, Zhang Lin-xin and Wang Jian-hua. 1988. Fusulinids, 240 pp., Sci. Press, Beijing. Skinner, J. W. and G. L. Wilde. 1965. Permian biostratigraphy and fusulinid faunas of the Shasta Lake area, northern California. Univ. Kansas Paleont. Contr., Protozoa, Art.6: 1-98, pis. 1-65. Skinner, J. W. and G. L. Wilde. 1966. Type species of Pseudofusulina Dunbar & Skinner. Univ. Kansas Paleont. Contr., Pap. 13: 1-7, pis. 1-4. Smith, G., J. C. Briden and G. E. Drewry. 1973. Phanerozoic world maps. In Hughes, N. F. (ed.), Organisms and continents through time, Palaeont. Assoc. London, Spec. Pap. Palaeont., (12), [Systematics Association Publication No. 9], pp. 1-42. Sugimura, A. 1972. Three new species of the genus Hayasakapora from Akiyoshi Limestone Group, Fusulinacean Biostratigraphy of the Akiyoshi Limestone Group, Part I 95

Japan. Bull. Akiyoshi-dai Sci. Mus. (8): 1-6, pis. 1-2. Sugimura, A. 1974. Some Permian Bryozoa from the Zomeki limestone, Yamaguchi Prefecture, Southwest Japan. Bull. Akiyoshi-dai Sci. Mus., (10): 1-8, pis. 1-2. Sugimura, A. 1985. A new Carboniferous species of Girtypora (Bryozoa) from the Akiyoshi Limestone Group, Southwest Japan. Bull. Akiyoshi-dai Mus. Nat. His., (20): 17-23. pi.7. Sugimura, A. and M. Ota. 1971. A bryozoan reef found near the lowest part of the Akiyoshi LimestoneGroup,Japan. Bull. Akiyoshi-dai Sci. Mus., (7): 57-63, pis.9-11. Sugimura, A. and M. Ota. 1980. Some Lower Permian Bryozoa from the Akiyoshi Limestone Group, Southwest Japan. Bull. Akiyoshi-dai Mus. Nat. Hist., (15): 47-58, pis. 3-5. Sugiyama, T. 1984. Heterocorallia from the Akiyoshi Limestone, Southwest Japan. Part 1. Systematic paleontology. Bull. Akiyoshi-dai Mus. Nat. Hist., (19): 27-67, pis. 1-7. Sugiyama, T. and K. Nagai. 1990. Growth forms of auloporidid corals in the Akiyoshi Limestone Group, Southwest Japan: Paleoecological studies of reef building organisms in the Akiyoshi organic reefcomplex I. Bull. Akiyoshi-dai Mus. Nat. Hist., (25): 7-25, pis.3-5. Sugiyama, T. and T. Haikawa. 1993. Checklist of Late Paleozoic corals and chaetetids described and/or illustrated from the Akiyoshi limestone area, SouthwestJapan. Bull. Akiyoshi-dai Mus. Nat. Hist., (28): 59-78. Sugiyama, T. 1939. Some contributions to the knowledge of the Palaeozoic of the Akiyoshi district, Mine-gun, Yamaguchi Prefecture. Jour. Geol. Soc. Japan, 46(544): 13-22. Thompson, M. L. 1948. Studies of American fusulinids. Univ. Kansas Paleont. Contr., Protozoa, Art. 1: 1-184, pis. 1-38. Thompson, M. L. 1951. New genera of fusulinid foraminifera. Cushman Found. Foram. Research, Contr., 2, Part 4: 115-118, pi. 13. Thompson, M. L. 1964. Fusulinacea. In Moore, R. C. (ed.), Treatise on Invertebrate Paleontology, Part C, Protista 2 (Sarcodina chiefly "Thecamoebians" and Foraminiferida by Loeblich, A. R. Jr. and H. Tappan), pp. 358-436, Geol. Soc. Am. and Univ. Kansas Press. Tikhvinskiy, I. N. 1965. K ekologii shvagerin. Paleont. Zhurnal, (2): 18-22. Toriyama, R. 1954a. Geology of Akiyoshi. Part 1. Study of the Akiyoshi Limestone Group. Mem. Fac. Sci., Kyushu Univ., Ser. D, Geology, 4(1): 39-97. Toriyama, R. 1954b. Geology of Akiyoshi. Part 2. Stratigraphy of the Non-calcareous Groups developed around the Akiyoshi Limestone Group. Mem. Fac. Sci., Kyushu Univ., Ser. D, Geology, 5(1): 1-46. Toriyama, R. 1957. Geology of Akiyoshi-dai. Research Report of the Akiyoshi-Dai Plateau. Board of Education of Yamaguchi Prefecture: 1-36. Toriyama, R. 1958. Geology of Akiyoshi. Part3. Fusulinids of Akiyoshi. Mem. Fac. Sci., Kyushu Univ., Ser. D, Geology, 7: 1-264, pis. 1-48. Toriyama, R. 1963. The Permian. In Takai, F. et al. (eds.), Geology of Japan, pp. 43-58, Univ. Tokyo Press, Japan. Toriyama, R. 1967. The fusulinacean zones ofJapan. Mem. Fac. Sci., Kyushu Univ., Ser. D, Geology, 18(1): 35-260. Toriyama, R. 1978. The Carboniferous and Permian boundary. In Editorial Committee for the Carboniferous Lexicon of Japan (ed.), The Carboniferous Lexicon of Japan, Geol. Surv. Japan, Report, (252), pp. 45-46. Uchiyama, T., H. Sano, and K. Kanmera. 1986. Depositional and tectonic settings of cherts around the Akiyoshi Limestone Group, Southwest Japan. Mem. Fac. Sci., Kyushu Univ., Ser. D, Geology, 26(1): 51-68, pis. 6-8. Ueno, K. 1989. Carboniferous and Lower Permian foraminiferal biostratigraphy in the Akiyoshi Limestone Group - Studies of the Upper Palaeozoic foraminifers in the Akiyoshi Limestone 96 Yasuhiro Ota

Group, Southwest Japan. Part. I. Bull. Akiyoshi-dai Mus. Nat. Hist., (24): 1-39, pis. 1-8. Ueno, K. 1991a. Pamirina (Permian fusulinacea) from the Akiyoshi Limestone Group, Southwest Japan. Trans. Proc. Palaeont. Soc. Japan, N. S., (161): 739-750. Ueno, K. 1991b. Upper Carboniferous fusulinaceans from the Akiyoshi Limestone Group, South west Japan. Trans. Proc. Palaeont. Soc. Japan, N. S., (163): 807-827. Ueno, K. 1991c. Early evolution of the families Verbeekinidae and Neoschwagerinidae (Permian fusulinacea) in the Akiyoshi Limestone Group, Southwest Japan. Trans. Proc. Palaeont. Soc. Japan, N. S., (164): 973-1002. Watanabe, K. 1991. Fusuline biostratigraphy of the Upper Carboniferous and Lower Permian of Japan, with special reference to theCarboniferous-Permian boundary. Palaeont. Soc. Japan, Spec. Pap., (32): 1-150. Wilde, G. L. 1971. Phylogeny of Pseudofusulinella and its bearing on Early Permian stratigraphy. In Dutro, J. T., Jr. (ed.), Paleozoic perspectives, A paleontobgical tribute to G. Arthur Cooper, Smithsonian Contributions to Paleobiology, (3), pp. 363-379. Wilde, G. L. 1975. Fusulinid-defined Permian stages. In Permian Exploration, Boundaries and Stratigraphy. West Texas Geological Society and Permian Basin Section, SEPM Publication: 75-65, 67- 83. Wilde, G. L. 1984. Systematics and the Carboniferous-Permian boundary. Neuvieme Congres International deStratigraphie et de Geologic du Carbonifere, Compte Rendu, 2: 543-558. Winkler P., C. F. 1990. SCCS Working Group on the subdivision of the Upper Carboniferous s. 1. ("Pennsylvanian"): A summary report. In Brenckle, P. L. and W. L. Manger (eds.), Intercontinental Correlation and Division of the Carboniferous System, pp. 297-306, Contributions from the Carboniferous Subcommission Meeting, Provo, Utah, September, 1989, Courier Forschung- sinstitut Senckenberg, 130. Yanagida, J. 1962. Carboniferous brachiopods from Akiyoshi, Southwest Japan. Part I. Mem. Fac. Sci., Kyushu Univ., Ser. D, Geology, 12(1):87-127, pis. 14-21. Yanagida, J. 1965. Carboniferous brachiopods from Akiyoshi, Southwest Japan. Part II. Mem. Fac. Sci., Kyushu Univ., Ser. D, Geology, 16(2): 113-142, pis. 25-28. Yanagida, J. 1968. Carboniferous brachiopods from Akiyoshi, SouthwestJapan. Part III. De- lepinea from a pyroclastic rock near the lowest part of the Akiyoshi Limestone Group. Trans. Proc. Palaeont. Soc. Japan, N. S., (72): 327-339, pis. 33-34. Yanagida, J. 1973. Carboniferous brachiopods from Akiyoshi, SouthwestJapan. Part IV. Margi nalia from the lowest part of the Akiyoshi Limestone Group. Bull. Akiyoshi-dai Sci. Mus., (9): 39- 51, pis. 1-2. Yanagida, J. 1979. The large Carboniferous Strophomenides from the Akiyoshi Limestone Group and their biostratigraphical significance. Proc. Japan Acad., Ser. B, 55(3): 109-114. Yanagida, J. 1983. A new schizophoriid genus from the Akiyoshi Limestone (Carboniferous brachiopods from Akiyoshi, Southwest Japan. Part V). Mem. Fac. Sci., Kyushu Univ., Ser. D, Geology., 25(1): 101-114, pis. 14-15. Yanagida, J., M. Ota and K. Nagai. 1977. On the faunas of the Millerella Zone in the Akiyoshi Limestone Group (Study of the Carboniferous faunas in the Akiyoshi Limestone, Part I). Sci. Repts., Dept. Geol., Kyushu Univ., 12(3): 139-146, pi. 13. Yanagida, J., M. Ota, A. Sugimura and T. Haikawa. 1971. On the geology of the northeastern part of the Akiyoshi limestone plateau. Sci. Repts., Dept. Geol., Kyushu Univ., 11(1): 105-114, pis. 7-10. Yamagiwa, N. and M. Ota. 1963. Faunas and correlation of "Uzura" quarry, Akiyoshi, Southwest Japan. Part 1. Corals. Bull. Akiyoshi-dai Sci. Mus., (2): 87-93, pis. 1-2. Yang Xiang-ning and Hao Yi-chun. 1991. A study on ontogeny and evolution of Robusto- Fusulinacean Biostratigraphy of the Akiyoshi LimestoneGroup, Part I 97

schwagerinids (Permian fusulinids). Acta Palaeont. Sinica, 30(3): 277-306, pis. 1-4. Zhang Zhi-cun. 1983. Zoning of fusulinids in the Upper Carboniferous Taiyuan Formation in western hills of Taiyuan, Shanxi. Jour. Stratigraphy, 7(4): 272-278, pis. 1-2. Zhang Zhi-cun. 1991. Study on fusulinid defined biostratigraphic boundary between the Carbon iferous and Permian. Bull. Yichang Inst. Geol. Mineral Resources, CAGS, (16): 43-50. Zhang Zu-qi. 1984. The Permian system in South China. Newsletters on Stratigraphy, 13(3): 156- 174. Zhou Tie-ming, Sheng Jin-zhang and Wang Yu-jing. 1987. Carboniferous-Permian boundary beds and fusulinid zones at Xiaodushan, Guangnan, eastern Yunnan. Acta Micropalaeont. Sinica, 4(2): 123-160, pis. 1-6.