Biostratigraphy and correlation of the Turonian - Coniacian succession and the Turonian - Coniacian boundary problem in the Far East Russia based on ammonites and inoceramids
TATIANA D./oNOVA' & ELENA A. YAZYKOVA1
1 VSEGEI. 74 Srednii p r 199106 St. Petersburg, Russia * University o f Silesia. Department of Earth Sciences. Lahortatorx of Paleontology Л Stratigraph\. Hfdzwska Str 60. PL-41-200 Sosnowiec. E-mail: yazykova4btiltra.cto.us.etiu.pl
ABSTRACT:
/c>NOVA. TD. & YA/VKOVA. К A. I **98. Bioxtratigraphv and correlation c f the Turonian - Coniacian succession an»l !hc Turonian Coniacian boundary problem in the Far fcBst Russia bused on ammoni- •«is and inoceramids. Acta (ieologii a Polonica. 4X (4), 4X'-444 Warszawa
The stratigraphy ammonite and inbccntmid content of ihe Turonian _ C oniacian deposits of Far fast Russia arc presented The cvolut№n 0f Monh Pacific ammonite* amj moceramids a» the boun dary of Ihe two stages was studied i,nd the levels of fundamental changes within the ammonite and i'loceramid biota are recognized. The established palaeobiogeogra&hic difference between the Sakhalin and Ihe North-East region palacobastns is reflected in the existence of two independent I'kbI zonal schcmcs The main criteria of the Turonian Coniacian stage boundary in the Far East of Russia were established on the basi4 of the two schemes. The Turoniim,'Coniacian (Т/Cl boundary i\ clearly marked by the change in the taxonomic diversity of the zom>| moceranud assemblages. It 14 defined at the buse of the lnoceramus unajimensii Zone The appc*rance of the endemic ammo nне species J'tmboicerax mthoens«■ Matsumoto is the ammonite criterion for recognising the T/C stage boundary in Sakhalin. This is supported by occurrences of ihe cosmopolitan Coniacian genera Peromceras and Lnrresieriq
ISTRODVmO.y Лш the high degree o f endemism of faunal assemblages from the Pacific palaeobio- Upper Cretaceous deposits are widely distrib geographie Realm. Moreover, numerous investi uted in Par East Russia, in Sakhalin and the Kuril gations in Russia, Japan. Australia. New Zealand, Islands; and also in North East Russia, within California and Alaska allowed two (northern and north-western Kamchatka, in the Koryakia southern) provinces to be defined in this huge Upland, and on the north coast of the Sea of realm (V ereshchagin 1964. K hudoley 1979). Okhotsk (Tcxt-fig. I )• They are represented most The part of the Pacific Realm discussed in this ly by marine deposits and contain rich murine fau paper belongs to the North Pacific province. nas with abundant ammonites and inoceramids. Within the Pacific Coast of Russia two faunal and The study of representatives of these two groups depositions! areas can be distinguished Sakhalin determined the characteristic species of ammonites and inoceramids from our collections, as well as from the collections of Dr. V.N. V ereshchagin , and Yu.G. M ir o l ib o v , both VSEGEI. St. Peterhurg, Russia. All of the speci mens are housed in the TSN1IGR Museum of VSEGEI in St. Petersburg, nos 10693. 11799. 11886, and 12580. 12632.12769. 12940.
PREVIOUS RESEARCH
Researches on the Cretaceous biostratigraphy of the Pacific Coast of Russia were begun by K rishtofovich (1932) and Bodylevskii (1937). Vereshchagin & M ikhailov (1958), Efimova (1955), and LiverovskaYa (1959a-b). In the 1920s and 1930s, the southern part of Sakhalin was intensively studied by Japanese geologists {e.g. Yabb 1927). Later the results of their researches were used for zonal subdivision of the Upper Cretaceous succession of Japan (M atsumoto 1942-43. 1959). The most impor tant contributions to the study of the Turonian - Coniacian fauna were made by Pergament Fig I. Location map of ihe investigated regions of Far East (1961. 1971. 1974), Vereshchagin (1963). Russia Ivanov & Pokiiialainln (1973), Pokhialaini* (1982), Vereshchagin & a t. 1965), Zonova (1970, 1974), Dundo & Efremova (1974). The and the North-East region (Kamchatka and most recent palaeontological studies were by Koryakia). Paleobiogeographically, the former Zonova and Yazykova (Zonova 1991, resembles closely Japan, whereas the latter is Yazykova 1992, Zonova & at. 1993). more similar to Alaska, particularly in respect of the occurrence of some species typical of North America. California and Vancouver Island. GEOLOGICAL SETTING T h e T u ro n ian - C o n iac ian seq u en ces arc- found (Text-fig. 1) in Sakhalin (the West In a tectonic context, the Koryak Upland and Sakhalin Mountains): and in North-East Russia, the north-western coast of the Kamchatka in the Anadyr-Koryakia region (Penzhina Ciulf. Peninsula form pan of the Cretaceous Koryak - Ugol'naya Bay and the Koryakia Upland) Kamchatka thrust and fold bell. This belt is the (Peroament 1961. 1971: Poyarkova 1987; Asian margin of the Pacific Ocean. It stretches ZONOVA & til. 1993). from the western coast of the Kamchatka The endemic species comprise nearly 809£ of Peninsula into the Koryak Upland and the the faunas from the T/C boundary sequences, Alaskan Peninsula. It consists of very complicat including many long-ranged taxa. Consequently, ed thrust sheets and fragments of Palaeozoic - development of refined zonal schemes is very Mesozoic island arcs, marginal sea and oceanic problematic, as is their correlation. complexes. At present, fragments of these struc The aim of the present paper is to confirm the tures are described as terranes (Sokolov 1992. position of the T/C boundary in Far East and Nokleberg 1994. Filatova 1995. K hldoley & North-Fast Russia, and to try to correlate this S o k o lo v (in press). The Koryak - Kamchatka level with other regions of the world. We carried thrust and fold belt formed as a result of mid- out detailed investigations of the numerous sec Cretaceous accretion. The Koryak - Kamchatka tions in Sakhalin and in North-East Russia and and the Verkhoyansk - Chukotka thrust and fold belts are unconformably overlain by «he Okhotsk developed at the continental margins of North Chukotka marginal volcanic beft (Sokolov and South America. This process coincided with 1992. Filatova 1995,Khudoley & Sokolov (in the highest rate of ocean-floor spreading of the press). Thus Sakhalin anil the Kuril Islands are Pacific. It caused the appearance of new conver elements of the extensive complex o f island arcs gent boundaries along Ihe continental margins and marginal seas that was formed in Jurassic - and a speeding-up of the subduction of the ocean Cretaceous time along the Pacific periphery. The ic plates. The supra-subductional calc-alkaline Okhotsk - Chukotka belt had its continuation in volcanism developed on the continental margins the Japanese - Korean - Chinese region (Lianshi (Z in k ev ich 1981, F ila tova 1995). The complex & RoNOFU 1988). in southeast Asia, and in east tectonic construction of the regions studied is ern Australia (M ollade & Najrin 1983). The a serious obstacle to the definition of clear strati- fragments of this global system of volcanic belts graphical boundaries. In Sakhalin the Turanian - Coniacian succes sions were studied in the West Sakhalin moun tains (Text-Fig. 2). These deposits belong to the Bykov Formation in the south of the island, to the Tymovsk and Verblud formations in the central part, and to the Arkovo Formation in the north. They are represented by rhythmic alternations of mudstones and sandy mudstones with thin inter calations of sandstones, luffitceous sandstones and sporadic marly fossiliferous concretions. The reference section for the Cretaceous deposits of Sakhalin is in the Naiba River valley Texi-fig. 3 in the south o f the island (PoYARKOVA 1987). It is the most complete and uninterrupted section available, which is the reason for it being chosen as the basis for this study. In addition, there are another 20 sections from different localities in the island. The maximum thickness of the Turonian - Coniacian succession in Sakhalin is 1300m . As mentioned above, North-East Russia is tectonically complex. The Turonian - Coniacian succession was studied there in the Koryak- Anadyr’ region (Text-fig. I). It comprises the famous Turonian - Coniacian succession on the Pen/hina Gulf and in the Mamet river valley
(P f.r o a m e n t 1971), in north-western Kamchatka (Text-fig. 4); and (he Penzhimt river section, in the Pontoncy and Slovutnye mountains on the spurs of the Pen/hina range. In Ihe north-eastern part of the region, successions ;irc available in the Anadyr’ river basin, along the coast of the Ugol'naya Bay and in the north-eastern part of the Koryak ia .Mountains. The Turonian - Coniacian successions in North-East Russia are represented by similar alternators of mudstone and sandy mudstone as in Sakhalin, with intercalations of sandstones, tuffaceous sandstones arid tulTaceous mudstones, Fig 2. Location map of the Turanian Cnniatiun sections in bentonites (volcanic clay) and marly concretions. ihe island of Sakhalin The latter commonly form concretion layers. The maximum thickness of the Turonian - Coniacian are now five zones in Sakhalin, comrising three succession in North-Easi Russia is 1000m. zones in the Turonian and two in the Coniacian, For a long time, previous workers recognized The same inoceramid zones are used in many different formations here, The authors of North-East Russia, except for Inoceramus tesh- the present paper follow the clussifieaton of ioensis - Mytiloides incertus Zone; which is V ereshchagin (1979). whereby the Turonian - replaced here by the the Inoceramus multiformis Coniacian deposits of the Penzhina Gulf Zone. The latter zonal taxon is probably the vic palaeohasin belong to the Penzhina Formation arious species of I. teshioensis. M oreover, the (=РеГ-АГ Formation in P erg a m ev t 1971). and Inoceramus mihoensis Zone from the Coniacian the deposits of Omgon Cape - to the Mainachsk o f S akhalin is not reco g n ised here, because there Formation. The Albian - Turonian succession of are no records so far of the zonal index. Ugol'naya Bay is the Ginterovsk Formation and the Coniacian - Early Campanian succession was Mytiloides off. labiatus Interval Zone named the Barykovsk Formation. This zone was first distinguished within the
Naiba section of Sakhalin by M a t s i m o t o 1NOCERAMID ZONATION (1959). In the studied areas, the zone is char acterized by M ytilo id es a ff. la b ia tu s (S c h io The authors worked out two independent local THEIMj, Inoceramus concentricus costatus schemes using inoceramids (Texl-figs 4,6). There Nagao & M atsi moto and I. umboceramus Zonova. The zonal interval is from the first appearance datum (FAD) of the nominative т я г г г • 553* Peroniceras sp. species to the FAD of Inoceramus hobetsensis .225s« N a g a o M atsum oto. In Sakhalin and Japan. z ~ -SFJT • 22* Fonestoria айишисН & < l_ *220 650 Even! M ytilo id es a ff. labiatus has been found in association with F a g esia sp. (Matsumoto ; 1973. Matsumoto & Muramoto 1978. < : POYARKOVA 1987). T he zo ne c o rresp o n d s to Inoceramus mihoensis Z z Jimboiceras m/hoense the zone of In o c e ra m u s nov. sp. aff. О Event Inoceramus saxonicus in Japan (Toshimitsu & is ° ■1018 о i- a l. 1995). 2 b The Pacific M ytilo id es a ff. labiatus Zone uwajimensis Event < probably corresponds approximately to the 5 ran g e o f Mytiloides labiatus ( S c h lo th e im ) , Л/. i к m ytilo id es (M antell). M. kosmatti (H ein z) z 3 O and M . h a ttin i (Elder) in the European and < LL Mediterranean realms (Kauffman 1978 a.b; Kauffman & a). 1978, W alaszczyk 1992. z > о Marcinowski & a l. 1996. Harries & al. CE I ° 1996). • 213, 214, 106 Э E * .227 v >> :l и-лвм! 1- -:;-d ’чтшт Inoceramus hobetsensis Interval Range Zone >• ~~~1 IB-к*/ -'ittgotoe a / . ibu rirm ii 1995). i /. tapiUtfur Tad Uunarcb Inoceramus multiformis Interval Zone I. oMraennii PergamENT (1971) first established this /. tw irnfbrmis /. teahtaemh zone in North-East Russia, on the coast of the I *iuU'ft»vn/i Penzhina Gulf. The present authors revise the I l*n»utriatus limits of the zone herein. The lower boundary is marked by the FAD of the index taxon. | / miroUtbovi The upper boundary is taken al the FAD of / t/WmelffUi* Inoceramus uwajimensis. Besides numerous I Htbtnti№irn%i.\ specimens of Inoceramus multiformis I nuceus Pergament. the characteristic inoceramid i. pratirutmiUtnt species occurring within the zone are /. n uceus ! /. :n,ainiitiw Z o n o v a , I. mamefensis Peroament, /. sub- I /. tu k/.f iru.\ m a m e te n sis Zonova, /. praeinconstans I. ivom Pergament, /. mirolubovi, I. tenuistriatus, I. I. *о'юанЫ .-i o ch o ticu s (Pergam ent), and scarce remains of I. orU* bornru Inoceramus teshioensis. I. krfik:o4ovhhl Pergam ent (1971) inferred that the deposits i mbgflntt;ianus of this zone represent the Lower Conia i mifkttnsii cian. However, Inoceramus multiformis co I I iawathital occurs with Turonian ammonites, such as I itonsiforwiis Jimboiceras planulatiforme (Jim b o ), N ippo- nites mirabilis Matsumoto and S c a p h ite s Fig. Stratigraphic distribution of the Turonian Coniacian p la n u s (Yabe). The age of this zone is therefore inoceramids in the RusMiin Pacific co»st lucceuion Late Turonian. Inoceramus uwajimensis Interval Zone Scaphites planus Interval Zone This /.one was first described from Japan and Vereshchagin (1977) distinguished the S akhalin by MATSUMOTO (19 59 ). It ranges from Scaphites planus beds within the Naiba section the FAD of Inoceramus uwajimensis to the FAD of Sakhalin. The present zone is proposed for o f Inoceramus amakusensis N a o a o & North-East Russia only. The zone ranges Irom M atsumoto, the Santonian index in the North the FAD of the index taxon to the FAD of Pacific province. In the studied areas, the /one is Jimboiceras planulatiforme (Jim во). characteri/cd by Inoceramus• uwajimensis < B esid es Scaphites planus (Yabe). the char including subspecies chirovoensis Zonova), /. acteristic ammonite species are Sc. perrini ochoiicus, I. verus (Pergament). I. lolmatchevi (Anderson). Sc. gracilis Y a b e , S c . pseudoae- Zonova, /. subgeinitzianus Zonova, /. m ihoen- q u a lis Y aB E, S c . ( Otoscaphites) yonecurai sis Matsumoto, I. kawashitai N o d a , /. incon- (Jim b o ), Xfesopuzosia pacifica Matsumoto, siunsiformis (Zonova), /. orlovkaensis Z o n o v a , Gaudryceras tenuiliratum Y a b e , Scalaritet and I. kryshtofovichi Z o n o v a . sc a la ris Jimbo and Diplomoceras sp. This zone is divided into two parts. In the (M atsumoto 1954. Poyarkova 1987). lower part small forms of /. uwajimensis p re The nominative species is a dominant form in dominate and are common, while in the upper Japan in the Upper and Middle Turanian succes part it is the large forms that predominate. The sions (Y abf 1910. T anabf. 1977). lower part additionally contains numerous Coniacian scaphitids. Its base is inferred to equate with the base of the Inoceram us Tt IRON! AN CONIACIAN (Cremnoceramus) rotundatus Zone in Japan L M ЩЖ J M I I1 (TOSHIMITSU & at. 1995) and probably corre Saiphuei ptamu sponds also to the same zone in Europe S c prrnm (KAUFMANN & al. 1996). The small forms of I. Sc. i/iu ih i uwajimensis are more widespread in the Penzhina succession, but the level with larger Sc pwiulntqmtn Sc p a rn u lu i shells is better developed in Sakhalin. The present zone corresponds to the zone of Sc. M ila n s ii the same name in Japan. Alaska and California Hvpfam k>гсгш vl (M atsu m o to 1959). V. uralaris Sc \r S', bacclm This comprises the interval from the FAD of Mr л (ум;-ли puctfii'a the index species to the FAD of Inoceram us f UJ'MKI ip. amakusensis Nagao & M aislmoto. This zone Z tlo a iisn m ihotntu was first distinguished within the Kaiba section RtmxHvrfm tY.;nmuu.\w'mv of Sakhalin by M atsum oto (1959). rem itonifn gtabnm Inoceramus mihoensis Matsumoto is found Г tp tg o m m in association with Peroniceras sp. and. at the extreme base, with Forresteria alluaudi Jim boiceiti p!armto G. itm rp l:ca tsm The present sludy has additionally led to the N ropbylintcw s ram ow m establishment of an ammonite zonal scheme for the Turanian - Coniacian succession of the Fig. 5. Strntigruphic distribution of I he Turanian Coniacian Russian Pacific Coast (Text-figs 5-6). ammonites in the Russian Рас I lie coast succession North-EastRussia S a k h a lin J a p a n Si & § A m m onoid A m m onoid 2 Inoceram id zones Inoceram id A m m onoid Inoceram id v; zones zones zones zones zones andsuhzones andsuhzones ------tnoceramus Pertmiceras Inner гати > Paralexaniles mihoensis sp. mihoensis , orirntalis 1. (Cordh eramus) upper kauashilal JD /п осе ram ил и Fonr steria tnoceramus Forrestfria Forrest eriu h x rw w i 3 itifuthli uwajimeniis alliuuli UbujhnrnMx nlliiadl uwajimensis < О Pm hyde mace ras Forresteria 1посет им» u mi/uvmc tHartehes) (Cremnoceramus t Л if Л pertrm orienst* roiimiUilus lower Subpriono- Subprionocyctus 1. lenuistrialus tnocerasmus I'.Hus sp. ' lesMoensu nepluni multiformis 1. teshioensh < upper Jimhttlcerax f>/anuUit(/onne Jimbaiceras Kt uruuticrrus / hohetsen u.\- z planulatiforme tnoceramus de^nanum Sf teraokal о tnoceramus hobetitnsLs Romaniceras hobetsrnsh Collognoniceras (Y.) ornatissimum\ wootlgari t.costatus middle 1 theveslewis- \t uihlu n уяп ш s H .•V/. aff. nodosoides Scaphites M\iiloide\ all Fagesia Mytiloides al l. Л / m\iifoMe.\ pUmits iahuuus Pscudaspidot-eras Ittbuilus sp. ftexmaum At aff. cotumbianus ^ lower ______SI siukcnsii . ■? Fig ft Turonian - Coniacian inoceramid and ammonoid conation applied lo Russian Pacific coast «accession by ihc author* and n comparison with ihc same of Japan [after TosHlMltsu & at. 1995) The Fagesia sp. Zone Y a z y k o v a (in Atabekian & a l. 1991). The boundaries of the present subzone are placed at Vereshchaqin (1977) distinguished “the the FAD and LAD of the nominative species. Beds w ith Fagesia sp." within the Lozovaya sec In the studied area this subzone is characterized tion in Sakhalin. The boundaries of the present by Romaniceras I Yubariceras) ornatissimum. subzone approximately correspond to those of Gaudryceras tenuiliratum, the small-sized forms the M ytiloides aff. labiatus Zone. In the studied o f Tetragonites glabrum (Jim b o), N ipponites area, the deposits of this subzone are character mirabilis Y a h f, Scapliites planus. Sc. puerculus ized by F agesia sp ., Scaphites planus Y ab b , (Jim bo), Sc . pseudoaequalis, Sc. gracilis, Scala- Zelandiies mihoensis M atsum oto < M ats имело rites sea laris. 1977) an d Gaudryceras (enuiliratum. In Jap an This subzone could correspond to the the upper part of the same interval is separated Romaniceras I Yubariceras) ornatissimum Zone off as ihe Fagesia thevestensis - Mammites aff. of the European Realm (M ortim ore 1986. Wood nodosoides Z o n e (TOSHIMITSU & al. 19 9 5 ). & al. 1987. G ale 1996). Representatives of the genus Fagesia are w id e spread in the Turonian of the Mediterranean Jimboiceras planulatiforme Interval /one Realm (Khakimov 1970, Collionon 1962, Seibertz 1979). This zone was first established in Japan (M atsumoto 1959). but Vereshchagin (1977) Roma nice ras (Yubariceras) ornatissimum subsequently recognised it in Sakhalin. The Тихон Range Subzone lower boundary of the zone is marked by the FAD of the index taxon. The upper boundary is "The Beds wilh Romaniceras ( Yubariceras) drawn at the FAD of Pachydesmoceras ornatissimum" were proposed for Sakhalin by m ihoense Matsumoto. The ammonite fauna recorded within the zone Jim bo. Sc . (O.) teshioensis (Y a b e ), Sc. f0.) is diverse, comprising Jimboiceras planulati- stephanoides Y a b e and Sc. (O.f klanuithensts fo rm e (Jim bo), Scaphites planus. Sc. pucrculus, Anderson (A labi shf.v 1989). There are numer Sc. pseudoaequalts, Sc. gracilis, Mesopuzosia ous additional records of the large-sized forms of pacifica, Gaudryceras tenuiliratum. Scalarites Tetragonites glabrum. scaiaris, Nipponites mirabilis, and the small The inferred Coniacian age of this zone is form s o f Tetragonites glabrum . supported by the occurrence of Forresteria allu The index laxon is also widespread in Japan audi. (MATSUMOTO 1454. 1959. 1977). Forresteria alluaudi Subzone Subprionocydus sp. Subzone “The Beds with Forresteria alluaudi" were dis 'The Beds with Subprionocydus sp,” were linguished by Pokhiala.nen (1988) within the first proposed for Sakhalin by Yazykova (in Koryk - Anadyr' region of North-Easi Russia. The Z o n o v a & at. 1993). The boundaries of the pre limits of the present subzone are placed approxi sent subzone are placed at the FAD and LAD of mately al the FAD and LAD of the index taxon Subprionocydus sp . T h e la tte r w as found in respectively. The Forresteria (F.) alluaudi Zone is association with Tragodesmoceras subcostatus recognised in the Middle Coniacian of Japan M atsumoto, Jimboiceras planulatiforme, (Toshimitsu & al. 1995). Species of the genus Mesopuzosia pacifica. Gaudryceras tenuiIira Forresteria arc indicators of the Coniacian in many tion and Tetragonites glabrutti. This subzone regions of ihe world (Kauffman & al. 1996). probably corresponds to the Subprionocydus neptuni Zone of Japan (Toshimitsu & a t. 1995) Peroniceras sp. Subzone and Europe (Hancock 1991). "The Beds with Peroniceras sp." were estab Pachydesmoceras mihoense Interval Zone lished within Ihe Naiba section of Sakhalin by Vereshchagin (in Resheniya 1982). Species of "The Beds with Pachydesmoceras mihoense" Ihe g e n u s Peroniceras are widespread in were first distinguished by Zakharov (Zakharov Coniacian successions worldwide (Klinger & & at. 1996). The present authors propose to regard WlEDMANN 1983). them as an independent /one, with the Naiba suc cession of Sakhalin suggested as ihe stratotype section. The lower boundary is placed al FAD of TURONIAN, COM ACIA N BOU N DA R Y the index taxon and the upper boundary al Ihe FA D o f Texanites (Piesiolexanites) kawasakii The Turonian - Coniacian boundary is one of (Kavada) of Ihe Santonian. the most discussed levels of the Upper Cretaceous B esides Pachydesmoceras mihoense. ihe char (Text-fig. 8). Recently the FAD of Crenmocerumus acteristic ammonite species occurring in the zone rotundatus (T rO g er non Fiege) was recommended are Forresteria alluaudi Matsumoto, as ihe basal boundary criterion for the Coniacian Peroniceras sp ., Gaudryceras denseplicatum slage (Kauffman & al. 1996). Ill Europe, this Jim bo. G. tenuiliratum, Neophylloceras ramosum boundary lies between the LAD of the ammonite (M eek ), Tetragonites glabrum, Damesites dame- Prionocydus germari and the FAD of the si Jimbo and Sc. puerculus (Jimbo). am m onite Forresteria I -Inoceramus hobetsensis Nagao & Matsi.moto, No. 34/12580; /. hobetsensis Zone, Middle Turonian. N-E Russia. Pen/hina Gulf coast, loc. 55 2 -Inoceramus aff. cuvieri Sowerby, No. 37/12580; /. hobetsensis Zone. Middle Turonian. N-E Russia, Pen/hina Gulf coast, loc. 54 3 - Inoceram us c f. capiiaius Zonova; /. hobetsensis Zone, Middle Turonian. N-E Russia. Pen/hina Gulf coast, loc. 53 PLATE 2 1 - Inoceramus nuceus Zonova, No. 49/12580: /. multiformis Z one. Upper Turonian. N-F. Russia, Karmalivayam River, loc.77 2 - Inoceramus multiformis PERGAMUNT. N o. 45/12580: /. multiformis Zone. Upper Turonian. N-E Russia, Niklekuyul River, loc. 631 3-5 - Inoceramus teshioensis Nagao & M atsumoto 3 -Specimen 47/12580; /. multiformis Zone. Upper Turonian; N-E Russia. Povorolnaya River, loc. 8 4 - Specimen 48/12580; /. multiformis Zone. Upper Turonian; N-E Russia. Penzhina Gull' coasl. loc. 010 5 - Specimen 228/10693: /. teshioensis M. incertus Zone. Upper Turonian; Sakhalin. Kuma River. Naiba River valley, loc. 26 6-7 - Inoceramus vents Pergamhnt; /. uwajimensis Zone, Lower Coniacian. N-E Russia. Asgichnivayam River, loc. 05/2 6 - Specimen 42/12580 7 - Specimen 43/12580 8 -Inoceramus aff. multiformis Pergamf.nt, Specimen 46/12580; I. teshioensis - M. incertus Zone, Upper Turonian, Sakhalin, Kuma River. Naiba River valley, loc. 26 PLATE 3 1 - Inoceramus nuceus Zonova, No. 51/12580; /. multiformis Z one. Upper Turonian, N-E Russia. Kannalivayam River, loc. 77 2-7 - Inoceramus mirolubovi Zonova. /. multiformis Zone. Upper T uronian 2-6 - Specimens 58-62/12580, N-E Russia, Kannalivayam River, loc. 77 7 - Specimen 62/12580, Pcn/hina Gulf coast, loc. 09 8 - Inoceramus uwajimensis Yehara. No. 26/8335. /. uwajimensis Zone, Middle Coniacian, Sakhalin. Bolshaya Orlovka River PLATE 4 1-2 - Inoceramus kawashilai N’ODA, 1 - No. 2/12575,2 - No. 274/10693; /. m ihoensis Zone. Upper Coniacian. Sakhalin. Krasnoyarka River, Naiba River valley, loc. 84 3 - Inoceram us aff. apicalis Woods. No. 55/12580; /. multiformis Zone. Upper Turonian. N-E Russia. Pen/hina Gulf coast, Truba spring, loc. 64a PLATE 5 1 - Inoceramus uwajimensis chyrvoensis Zonova. No. 8/12025: /. uwajimensis Zone, N-E Russia. Golodnyi slreacy, Penzhina Ri ver Valley, loc. 108 2-4 - Inoceramus mihoensis Matsumoto; /. m ihoensis Zone, Upper Coniacian. Sakhalin. Naiba River valley. loc. 551 2 - Specimen 1/12575 3 - Specimen 10/12575 4 - Specimen 6/12575 PLATE 6 1 , 9 - Inoceramus tolmatchevi Zonova; /. uwajimensis Z one, Lower Coniacian, N-E Russia, Ugol’naya Bay. loc. 85/3 2, 8, 10 - Inoceramus uwajimensis Yehara; /. uwajimensis Z one. Lower Coniacian 2 - loc. 540, N-E Russia. Koryak Upland 8 -N o. 131/12765; I. uwajimensis Zone. Lower Coniacian. Sakhalin, Malaya Orlovka River, loc. 44 10-N o. 130/12765, / uwajimensis Zone. Lower Coniacian. Sakhalin. К hoe River 3-5 - Inoceramus subgeinitzianus Z o n o v a 3-N o. 11/8335, /. uwajimensis Zone, Lower Coniacian, Sakhalin, Agnevo River, loc. 13Id 4 No. 9/8335; I. uwajimensis Zone. Lower Coniacian, Sakhalin, Agnevo River, loc. 13 Id 5 -N o. 10/8335, /. uwajimensis Zone, Lower Coniacian, Sakhalin. Bolshaya Orlovka River, loc. 216 6 - Inoceramus uwajimensis chirovoensis Z o n o v a , / . uwajimensis Zone, Lower Coniacian, N-F. Russia, Pen/.hina River Valley, loc. 108 7 - Inoceramus krishtofovichi Zonova; /. uwajimensis Z o n e, Lower Coniacian, N-E Russia. Pen/.hina River Valley, loc. 108 PLATE 7 1-2 - Romaniceras (Yubariceras) ornalissimum (Stoliczka) 1 Specimen 12693. Romaniceras ( Yubariceras) ornalissimum Subzone, Middle Turonian. Sakhalin, Naiba River, loc. 38 2 - Specimen 3/12632: Romaniceras ( Yubariceras) ornalissimum Sub/one. Middle Turonian, Sakhalin, Polyakovka River, Gastellovka River Valley, loc. 1091 PLATE 8 1 -Scalariies venustutn Yabe, No. 38/11799; Jimboiceras planulati- fo rm e Zone, Upper Turonian. N-E Russia. Pen/.hina Gulf Coast 2 - Scalariies scalar is Jimbo, No. 30/11799: Jimboiceras planulati- fo rm e Zone. Upper Turonian. N-E Russia. Penzhina Gulf Coast 3 - Hyphantoceras cf. reussianum (SchlO tlr). No. 29/11799: Jimbo- it eras planulatiforme Zone, Upper Turonian, N-F Russia, Pen/hi- na Gulf Coast • 1 PLATE 9 1,10 - Scaphites cf. perrini Anderson, 9 - No. 32/11799: Scaphites planus Zone. Lower Turonian, N-E Russia, Penzhina Gulf Coast, loc. 320 2-3,7-8, 11 - Scaphites pseudoaequalis Yabe; 7 - No. 50/11799; Scaphites planus Zone. Lower Turonian, N-E Russia. Pen/hina Gulf Coast, loc. 320 4 -Scaphites (Scaphites) p la n u s Y ab e; Scaphites planus Zone, Lower Turonian, N-E Russia, Pen/.hina Gulf coast, loc. 320 5-6 - Scaphites (Scaphites) gracilis Yabe. 5 - No. 31/11799: Scaphites planus Zone, Lower Turonian. N-E Russia. Penzhina Gulf Coast, loc. 320 9 - Scaphites (Otoscaphites) teshioensis (Y a b e); Scaphites planus Zone, Lower Turonian, N-E Russia. Penzhina Gulf coast, loc. 320 12 - Scaphites {YezoJies) puerculus (Jim bo); Scaphites planus Zone, Lower Turonian, N-E Russia. Pen/.hina Gulf coast, loc. 320 13 - Gaudryceras tenuiliratum Y ab e; Scaphites planus Z one, Lower Turonian, N-E Russia, Penzhina Gulf coast. Asgichnivayam River, loc. 05-a PLATE 10 1-4, 9 - Scaphites (Otoscaphiles) teshioensis (Yabe); 4. 9 - Jimboice- ra.s planulatiforme Zone. Upper Turonian. N-E Russia. Penzhi- na Gulf Coast. Asgichnivayam River. Iocs. 05. 320; 1. 3 - ju venile form Scaphites spp. Zone. Lower Coniacian, N-E Rus sia. Omulnaya River. Penzhina River Valley, loc, 35 5 , 6 - Scaphitespseudoaqualis Y a b e . Scaphites planus Zone. Lower Turonian. N-E Russia. Penzhina Gulf Coast, Asgichnivayam River, 11 - loc. 2088; 12 - loc. 320 2 , 7 , 8 - Scaphites (Yezt/iftrs) puercutus (Jim bo) 2 -Lower Coniacian. Scaphites spp. Zone. Omulnaya River. Penzhina River Valley, loc. 35 7 - Scaphites planus Zone, Lower Turonian. N-E Russia. Penzhina Gulf Coast, loc. 65 8 -N o. 49/11799; Lower Coniacian, S ca p h ites spp. Zone, Ugol'naya Bay, loc. 14a . 10-11 — Gaudryceras ten uilirattnnY 10 Specimen 32/12769; JimMict/rux mihaense Zone. Coniacian, Sakhalin. Naiba River, loc. 551 I I - Specimen 9/12632; Scaphites planus Zone. Lower Turonian, N-E Russia. Omgon Cape 12 - Tetragonites glabrunt (Jim bo); Jimboiceras planulatiforme Zone. Upper Turonian, N-E Russia. Penzhina Gulf Coast. Asgichnivayam River, loc. 03/2 PLATE II 1 - Jimboiceras planulatiformc (Jim bo); Jimboiceras planulaliforme Zone. Middle Turonian, N-E Russia, Penzhina Gulf Coast, Asgichnivayam River, loc. 148 PLATE 12 /bJyyUa-occtra* 1-2 - ЛшЫйтгм m ih o e m t' Matsumoto, I - No. 391/10693, 2 - No.31/12769; w nuhoensc Zone,Coniacian, Sakha lin, Naiba River, Iocs. 551, 550 PLATE 13 1 - Gaudryceras detiseplicatum Jimbo. No. 5/12632; Forresteria alluaudi Subzone. Middle Coniacian. N-E Russia. Koryak Upland. Melkaya River, loc. 3050 2 - Pachydesmoceras mihoense Matsumoto; Pachydesmoceras miho- ense Zone, Coniacian. Sakhalin. Naiba River, loc. 550 PLATE 14 1 - Neancyloceras aff. pseudoarmatum SchiX.ter, No. 25/11794; Jim - boiceras planulatiforme Zone, Upper Turonian. N-E Russia. Pen- zhina Gulf Coast, loc. 31 2 - Gaudryceras denseplicatum Jim bo; Jimboiceras planulatiforme Zone. Upper Turonian, N-E Russia, Penzhina Gulf Coast, Asgichnivayam River, loc. 145