Platysolenites, other animal fossils, and the Precambrian-Cambrian transition in Norway

SVEN FØYN & MARTIN F. GLAESSNER

Føyn, S. & Glaessner, M. F.: Platysolenites, other animal fossils, and the Precambian-Cambrian transition in Norway. Norsk Geologisk Tidsskrift, Vol. 59, pp. 2�6. Oslo 1979. ISSN 0029-196X.

The late Precambrian and Lower Cambrian autochthonous sedimentary sequences in northern Norway and adjoining areas and their fossils are reconsidered, and the available specimens are re-described. One Lower Cambrian foraminiferal fossil (Spirosolenites spira/is) and one Late Precambrian medusoid coelenterate (Kullingia concentrica) are named as new genera and species. The thickness changes and breaks in sedimentation in the platform cover compared with the 'miogeosynclinal' Digermul section are demonstrated. Possible biostratigraphic zones, age determinations, and correlations with the Late Precambrian and Early Cambrian fossiliferous rocks of the East European Platform are suggested.

S. Føyn, Norges geologiske undersøkelse, Oslo-kontoret, Drammensveien 230, Oslo 2, Norway. M. F. Glaessner, Centre for Precambrian Research, University of Adelaide, Adelaide, South Australia 5000.

.The autochthonous or para-autochthonous Late particularly the occurrence of breaks in deposi­ Precambrian-Cambrian sedimentary deposits of tion. Their palaeogeographic and geodynamic Norway may broadly be divided into the follow­ evaluation will have to await further studies on a ing four kinds: wider scale which are beyond the scope of this Miogeosynclinal sediments of eastern Finn­ contribution. mark, northern Norway, ranging from Riphean Tubes of Platyso/enites antiquissimus Eich­ through Vendian and Cambrian to Tremadocian. wald were found early in this century in the Two tillite formations occur. Dividal Group in Norrbotten (Moberg 1908),

· The Dividal Group, formerly also called the Troms (Vogt 1918) and Finnmark (Holtedahl 'Hyolithus Zone', a relatively thin sequence of 1918). Vogt (1924) found Platysolenites antiquis­ platform sediments resting with erosional con­ simus Eichwald in Lower Cambrian beds above tact on the Precambrian crystal-line basement. the sparagmite sequence at Ringsaker in the The Group occurs along the margin of the Mjøsa district of southern Norway (Fig. l, loe. Caledonian mountain range in the districts of l). Norrbotten (Sweden), Enontekis (Finland), Because of the thrust plane, the Dividal Group Troms and Finnmark (Norway). It is everywhere is not geographically continuous with the confined upwards by thrust planes of Caledonian miogeosynclinal sediments of the Laksefjorden, age. Tanafjorden and Varanger areas. The four infor­ The 'sparagmite' sequence of southern Nor­ mal members I, Il, Ill and IV of the Dividal way, considered to be deposited mainly in basins Group at Halkkavarre (FØyn 1967) have - formed by faulting. One glaciogenic unit occurs, member to member - a striking resemblance to the Moelv Tillite, generally accepted as an equi­ the three members of the Stappogiedde Forma­ valent of the Upper Tillite of Finnmark. The tion and the lower part of the Breivik Formation. sparagmite sequence is overlain by beds contain­ The lowermost member of the Stappogiedde ing Lower Cambrian fossils. Formation, the Lillevatn Member (Banks 1970), Cambrian strata resting with erosional contact follows the Mortensnes Tillite Formation ('Up­ on the Precambrian crystalline basement of per tillite') with transitional beds. Guided by the southern Norway. lithologies, Føyn in 1966 succeeded in finding We have attempted to add detail and clarity to Platysolenites antiquissimus Eichwald in the this agreed broad stratigraphic framework and to Breivik Formation at Kunes (Fig. l, loe. 6, see indicate by means of stratigraphic and also Føyn 1%7). The correlation thus made was palaeontological evidence the possibilities of later confirmed by Banks' work on trace fossils dating and correlation of its subdivisions and (Banks 1973). 26 S. Føyn & M. F. Glaessner NORSK GEOLOGISK TIDSSKRIFT l (1979)

Fig. l. Localities on the Scandinavian Peninsula represented on Figs. 2 and 3 and in the text. The thick line indicates the eastern erosional border of the Caledonides. Symbols: M-Mjøsa, D-Dividal, P-Porsangerfjorden, L-Laksefjorden, T-Tanafjorden, V-Varangerfjorden. I-Ringsaker, 2-Tornetrask, 3-Ruogooaive and Dorrovarre, 4-Avevagge, 5-Halkkavarre, 6-Kunes, 7-Di­ germul halvøya, 8-Eastern Tana. The localities 2-5 represent the Dividal Group.

In 1967 Føyn found Platysolenites also at The Platysolenites speeimens eolleeted by eastern Tana (east of Tanafjorden, Fig. 1, loe. 8) Føyn at Halkkavarre (Fig. l, loe. 5) and Kunes (FØyn 1967, 'Addendum': 78) and in 1969 Banks in 1966 were deseribed by Hamar (1967). The found Platysolenites on Digermul halvØya (loe. eolleetion of fossils made in l %7 from Kunes 7) on the west side of Tanafjorden (Banks and eastern Tana is examined and deseribed by 1970). In both those areas the Platysolenites Glaessner in the present paper, together with horizon is situated about 150 m above the base of most of Vogt's speeimens. Some speeimens de­ the Breivik Formation. seribed by Hamar have been re-examined. NORSK GEOLOGISK TIDSSKR!Ff l (1979) Platysolenites and other animalfossils 27

sp., and Lingulella sp.', thus corresponding to Stratigraphy the uppermost part of the Lower Cambrian of southern Scandinavia. The alum shale formation Th e Dividal Group - a link between is considered to be of Middle Cambrian age Finnmark and southern Scandinavia (Kulling 1964: 142). The total thickness of the four units of the Of very great importance are the fossils found Dividal Group at Halkkavarre (loe. 5) is 230 m. It by Kulling during the years 1959 to 1966 in the decreases towards the southwest through Finn­ Middle sandstone formation (C) in the mark and Troms to Norrbotten, being at Ave­ Tornetrask area and identified by him as 'Sprig­ vagge (loe. 4) 80 metres (Vogt 1967) and at gia annulata Southcott' (Kulling 1972, figs. 113 Tornetdisk (loe. 2) 50 m (Kulling 1964 , 1972, and 114) . He also records trace fo ssils in the Vogt 1967) . The 'four units' pattern, however, is same unit C and in the underlying unit B. A persistent. 'Problematicum' fo und by Moberg (1908 , pl. l, According to Kulling's and Vogt's description fig. l) in the Lower shale formation (B) has been of the lithologies and to the occurrence of determined by Vida! (1976 b) to be algae of the Platysolenites , the following correlations are genus Vendotaenia Gnilovskaya, considered to evident: be of Vendian age . Vida! mentions that Ven­

Kul/ing Vogt Føyn dotaenia occurs also in unit C. We conclude that Middle shale formation Niveau D Member !V most of the unit C of the Dividal Group at Middle sandstone formation Niveau C Member Ill Tornetrask is of Late Precambrian age, and Lower shale formation Niveau B Member Il consequently also Member Ill at Halkkavarre Lower sandstone fo rmation Niveau A Member l and fu rther the lowermost part of the Mann­ For convenience, Kulling's four informally draperelv Member. named fo rmations as well as Vogt's 'niveaus! will in the following be referred to as units A, B, Th e Precambrian-Cambrian transition in C, and D of the Dividal Group. eastern Finnmark The decrease in thickness towards the south­ west especially applies to the three lowermost The succession of sedimentary rocks on Di­ units. The deposition of the basal unit may have germul halvøya west of Tanafjorden (Fig. l, loe . been moderately diachronous, the beds young­ 7) seems to have been deposited continuously ing during the transgression towards the south fr om the Upper Tillite, including the transition and southwest. from the tillite to the next member. No signs of Platysolenites antiquissimus Eichwald occurs any stratigraphical break have been observed. in unit D. From the same unit Kulling (1964) The stratigraphical distance between the Upper reported the occurrence of Platysolenites Tillite and the Platysolenites horizon is 650 to 700 lontowa Opik, Volborthella tenuis Schmidt, and m, and above this horizon the Lower Cambrian Hyolithes sp. It is not known whether these beds comprise around 1000 m. Transitional beds fossils occur together in the same bed. The trace spanning the Precambrian-Cambrian boundary fo ssil Monocraterion reported fr om the lower­ should be present. most beds is now stated by Kulling to have come Based on trace fossils and on the Platysole­ fr om the overlying 'Upper sandstone formation' nites horizon, Banks suggests that the transition (pers. comm. to .M.F.G.). In addition, Vogt beds comprise the Manndraperelv Member and reports from Iocalities farther to the northeast the part of the Breivik Member below the Torellella sp. and a gastropod 'Straparolina ' sp. Platysolenites horizon (Banks 1970, Banks et al . This fauna zone thus belongs to the lower part of 1971). The base of the Breivik Member seems to the Lower Cambrian. be preferred as the local Precambrian-Cambrian In Norrbotten and Troms the succession con­ boundary , as the Manndraperelv Member is tinues upwards with the following three units of marked as 'Precambrian and ?Cambrian' whilst Kulling (Vogt's terms in brackets): the Breivik beds below the Platysolenites hori­ 'Upper sandstone formation' (E), 'Upper zon are marked 'Cambrian and ?Precambrian'. shale formation' (F), and 'Alum shale formation' Similary, Daily ( 1972) finds it 'logical to extend (G). The upper shale formation (F) has yielded the Lower Cambrian boundary to at !east the the ft>ssils 'Strenuella linnarssoni Kiær, El­ base of the Breivik Formation', as the trace lipsocephalus nordenskioldi Linnarsson, Obolus fo ssil Phycodes pedum · Seilacher is first seen 28 S. Føyn & M. F. Glaessner NORSK GEOLOGISK TIDSSKRIFT l (1979)

U Scole Paradoxides :I Metres l Skolitflos Diplo- 1600 i crat erion i Syringo- " 1 morpfla o 1 Cruz iana 0 1500 i Holmia sp. � i � � l .. .. .,o.c 1400 l l :Jg;: ·- oe o u l t----- � ., 1300 Diplo- .oo .. l cra t�rion c; � l Cruziana � -.J l .. 1200 � l o i _, l i 1100 i i l 1000 trace / fossits l " i o 900 l .. _c: thrust rocks / • o o thrust rocks � E ·� => .. .c -A t o E Alum sh. : G l;; ,;;-Sti:- IL O 800 ..--; F Strenuaeva : u · shale rocks -'/ 1--=====:-iStrenuaeva " thrust .X .. u 1--==:...... ---1 ------/ Upp•r sandstone .. :i Paradoxides E ··;- sandstone :a.. : a. l l------c-i .. o 700 1--::P""I a- t::-=s""o�l 0.=.ne .:.,;:,0 ,0t:.:. e"-is � Platysolenites · " Platysol�nites Platy- .. -' � o : O s ha o : 1 e : li solenites "' l : ._:. 1-"n-"T'Y'rr"-r"i... : � l ; o o � l 600 .. . Ringsaker Rusophyc i/s � E l Quartzite 1-r--,/Tlll'"ll":-i Pflycodes l .3"-1 Member pedum 1 l "' hiatu s :o; hiatus : o hiatus(?) .o 500 l i .a 1 T '• "' .-,:, z 11 01 :�: > ... �� Vardal : 1 t � Sandstone : > : ,.. simple � l i > Member burrows �l 1: :c: :c � j 400 l ���-��l n -�7-�-�. �. �o�o�o�o :-i7-��m�·�l�b��­ r; l u-i/ "-t r"Yq,"-tr"aY.Y _;__;.I"n'>t-T''r-'in-"t.,� � 1 l �,-!K4" . : �P \ simple burrows l ; � � l l \: n 300 l I o o t----:;_ l l .\, o l simple ..å-.l l burrows : hiatus(?) l � � 1 (first 200 l l ,. -� 1 l l l to1��i� !J 'E � l l l l l � � l l �ø 100 l l �l " c: I t--.-­ o \ kr• Fm. .!�.o -� ,;; E s� � � E M�lv Tillit• Mortensnu E

o Tillito Fm. Uo u t------i .. Pr.cambrian Pre ca m brien Precambrian .. gneiss 0.. gneiss gneiss

Ringsaker Tor netråsk Avevagge Halkkavarre Digermul Mjosa district Norrbotten Troms Fi nnmark Finnmark (L o c. l) (lo c. 2) (lo c. 4) (l o c. 5) (loe. 7) NORSK GEOLOGISK TIDSSKRIFT l (1979) Platysolenites and other animalfossils 29

within 3 m of the base of this formation. He also 'Spriggia' fossils and Vendotaenia below the suggests that the underlying Manndraperelv leve! of the Mortensnes Tillite and for this plac­ Member is of possible Cambrian age. ing there is no evidence. According to Vida! The view of the aut hors of the present pa per is (1976a:47) it is also contrary to his micro­ shown in Figs. 2 and 3. In the main it concurs palaeontological findings. with that of Banks and of Daily. The Di vida! At Avevagge (Fig. l, loe. 4) in Troms, Vogt Group, however, has been taken into considera­ recorded a peculiar, 0.3 m thick bed of conglom­ tion as an important correlation link between erate with a strongly yellowish brown weather­ Finnmark and southern Scandinavia. lf a Pre­ ing coating, in the uppermost part of unit C (Vogt cambrian age of Kulling's medusoid fossils and a 1%7: 55). Cambrian age of Phycodes pedum are accepted, In the Mjøsa distri et (Fig. l, loe. l) the well­ the Precambrian-Cambrian transition in eastern known thin conglomerate la yer at the base of the Finnmark is represented by a part of the Mann­ fossil-bearing Cambrian strata probably marks a draperelv Member. break in deposition. The magnitude of time of this hiatus may, however, be rather limited. Noteworthy in this respect is the statement of Gaps in the stratigraphical columns Skjeseth that in his opinion too much stress had One hiatus is marked in the columns of the been laid upon this non-angular unconformity Dividal Group, and two in the sequence of the (Skjeseth 1%3: 34). Bergstrom (1970) and Daily Mjøsa district. A question mark (in brackets) (1972) include the Vangsås Formation (Vardal means that the hiatus does not manifest itself and Ringsaker Members) in the Lower either lithologically or palaeontologically and Cambrian, mainly because of Skjeseth's record thus has been inferred by a 'Jack of thickness' of Skolithos, Monocraterion, and Diplocraterion relative to the succession of eastern Finnmark. in the upper part of the Ringsaker Quartzite. At Halkkavarre, instead of one hiatus above Member Ill, there may be more breaks within the lower part of Member IV. So also in the Mjøsa district: unrecorded breaks within the Some significant fossils from the Vardal Member may exist. Precambrian-Lower Cambrian At Luopakte, south of the lake Tornetrask strata of northern Norway and (Fig. l, loe. 2) in Norrbotten, a conglomeratic adjoining areas bed in the upper part of unit C indicates a 'stratigraphical break'. 'This stratigraphical Lower Cambrian break occurs immediately above the Spriggia­ bearing shale' (Kulling 1972: 166). North of Tornetrask, Kulling (1964, 1972) recorded a Platysolenites antiquissimus polymict breccia in that position, the Vakkejokk Eichwald breccia, containing subrounded blocks of Pre­ Figs. 4A-D, 5A. cambrian granite of various sizes, sandstones, and shale fragments, all in a shaly matrix. Kul­ P. antiquissimus Eichwald, 1860, 678, pl. 3, fig. 19; Schmidt, 1888, 26, pl. 2, fig. 22-23; Moberg, 1908, 29, pl. l, fig. 12; ling collected 'Spriggia' fossils about l m below Holtedahl, 1918, 129, pl. 17, fig. 2; Vogt, 1924, 289, fig. 4; the breccia (at a locality about 7 km east of Yanishevsky, 1926, 109-111, fig. 7; Howell, 1962, W 165, fig. Vakkejokk) (Kulling 1972: 164, fig. 127). Kulling 104.4; Hecker & Ushakov, 1962, 444, pl. 3, fig. 9; Glaessner, ascribed the formation of the breccia to the 1963, 9; Hamar, 1967, 90, pl. l, fig. l, 3, 5-7, pl. 2, fig. l (3), 3, 4, 7, 8; Glaessner, 1978, 62-3. action of a coid climate, and correlated the

Vakkejokk breccia with the U p per Tillite of Finn­ Material. - Numerous fragments in specimens. mark (Kulling 1972, fig. 127). As shown in Fig. 2, PMO 25105, PMO 25092-3, PMO 47199, PMO the authors do not agree with his correlation, 70500, PMO 97816-22, PMO 97825-49, PMO because Kulling's correlation would place his 98554-6.

Occurrence. - Three localities at eastern Tana (Fig. l, loe. 8), described by Føyn (1967, Ad­ Fig. 2. Correiation of sequences across the base of the dendum) and Kunes (loe. 6) south of Lakse­ Cambrian at some Iocalities in Scandinavia. Correlation lines: fjorden; also from Dorrovarre and Ruogooaive, ----- biostratigraphic, ------lithostratigra­ phic, -·-·-·-·-·-·-·-·-·- chronostratigraphic. see Vogt, 1967 (loe. 3). 30 S. Føyn & M. F. Glaessner NORSK GEOLOGISK TIDSSKRIFT I (1979)

Remarks. - As this fossil has been previously Specimens from the Blue Clay of Leningrad discussed, it will suffice to comment here on where overburden pressure was minimal show certain peculiarities of preservation and on some clearly the constituent grains of the agglutinated differences between taxonomic views on mat­ tubes (Glaessner 1978). The distinctness of erial from northern Norway expressed by Hamar transverse annulation and grooving varies in the and other views based on the study of Baltic present material from strong and regular with material. Hamar (1967) emended the diagnosis of convex areas between the grooves (Hamar l %7; Platysolenites to 'Small siliceous-calcareous pl. l, fig. l, 3) to finer and less regular grooving helical-shaped tubes most commonly found O.c. fig. 5, 7) and finally to lineations which are broken into pieces which are straight or bent. only faintly visible across smooth tubes (Fig. Outer surface annulated, wall thickness var­ 4D). The spacing of transverse grooves as meas­ iable'. This emendation is not acceptable. ured on the new material is within the limits Hamar reports '150 fragments of which 4 are given by Hamar. The fossils occur at some helical-shaped', surely not a sufficient basis for localities, e.g. Kunes, as single, broken, com­ declaring this shape a diagnostic character of pressed tubes about l mm wide and 5-1O mm Platysolenites. A bo ut 17 complete or long; at the Varanger localities they occur in fragmentary helical specimens were found in the some pieces of shale as abundant accumulations smaller amount of material discussed here. of similar, small tubes, while in others there are There were no transitions from the straight to the single fragments up to 30 mm long and over 3 spiral forms which are therefore described as a mm wide. The wall thickness varies from 0.3 to new genus. Some bent fragments of tubes with over l mm between specimens but remains un­ the characters of Platysolenites may be the re­ changed throughout the length of the tube. There sult of rock pressure. It should also be noted that is at present no morphological evidence on the generic diagnosis of Platysolenites in Howell which to separate taxonomically the few large l %2 is confined to peculiarities of preservation specimens which are over 3 mm wide from the and does not retlect the morphology of the genus many small ones in the 0.9 to 2 mm range.

and its type species. The tubes are not 'calcareo­ Systematic position. - Comparison of Pla­ siliceous' but siliceous in composition, with the tysolenites with Bathysiphon has shown con­ possible exeption of specimens from one locality vincingly that the Cambrian genus should be in Estonia mentioned by Schmidt (1888) and placed in the Foraminiferida rather than the Opik (1926). These may not be identical with the Annelida (Glaessner 1963, 1978). The new mat­ type species (Glaessner 1978). In this context it erial differs from the previously examined speci­ is worth noting that in the tube walls of some of mens mainly in the silicification of the tubes. It the specimens there are small rhombohedric does not contribute significantly to the discus­ cavities which appear to represent dissolved sion on the systematic position of the genus. dolomite crystals (Fig. 4B). An incorporation of calcareous material in tube walls of Platysole­ nites, though not proven, appears possible wherever such grains may have been available. Genus Platysolenites Pander, 1851

The second character described by Howell as Type species. - P. antiquissimus Eichwald, 'tlattened, with sides bent upward' is entirely a 1860.

mechanical effect of post-mortem deformation in Generic diagnosis. - Cylindrical tubes, mainly fossilization and occurs only in specimens lying straight, both ends open, thick walls consisting on bedding planes exposed to vertical pressure. of small quartz grains with transverse layering This produces J- or U-bends in the lateral parts which is often marked externally by closely to of the cross section of the tube and collapse of widely spaced grooves; the diameter of the tubes the cavity. The specimens from Scandinavia are remains generally unchanged during growth, preserved in shales which were subjected to their width varies from less than l to over 3 mm, heavy overburden pressure. It has caused peculiarities of preservation of Platysolenites, Fig. 3. A part of Fig. 2, on a larger se ale, with some more including silicification of the tests which resem­ details. Left: Ringsaker column, right: Tornetriisk coiumn. ble cryptocrystalline chert. Under the scanning According to Kulling, the stratigraphic break occurs at Luopakte immediately above the· shale with Kullingia, i.e. electron microscope they are seen to be within the upper part of the 'Middle sandstone', Unit C. See p. traversed by thin sheets of secondary silica. 29. NORSK GEOLOGISK TIDSSKRIFT l (1979) Platysolenites and other animal fossils 31

i hrust rocks

Atum shale

U.sh. trenuaeva Al um shale 11 S

Puradoxides l . c Strene U.ss . � 7CVa 1/olmia trace fossils Vl Volborfhella u Mobcrgclla .:�� �?l[{,f�.:�oJf"J[/1{,�2 �

hiatus

S kolithos Monoc ru ter ion Diplocraterion

Ringsaker Quartzite Member hiatus

Vardal S nd s tone a Memler with hiatus within{?) below(?), and a bove (?)

Il i n a M.ss. Ku gi s h. f s s L. trace o i l s l. ss. and cgl.o o o o � o- o o 32 S. Føyn & M. F. Glaessner NORSK GEOLOGISK TIDSSKR!Ff l (1979) NORSK GEOLOGISK TIDSSKRIFT l (1979) Platysolenites and other animalfossils 33

their length may exceed 30 mm; in larger sped­ umbilical side than on the spiral side, the incom­ mens the wall may be 0.9 mm thick. The tubes pletely evolute coiling leaving earlier whorls are often compressed by compaction. The genus visible from both sides; initial coil not preserved; is known from the Jower part of the Lower wall thick, outer surface with irregular, trans­ Cambrian of northern Europe and the East­ verse growth lines. European Platform from northern Russia to Measurements. - Diameter (maximum) from southern Poland and the Ukraine. 2.25 to 4.5 mm but reaching about 6 mm in one incomplete spedmen; width of outer whorls 0.75-l mm. As there are no complete free sped­ mens and those in the matrix seem to be some­ Spirosolenites spiralis Glaessner, what flattened, the height cannot be measured nov. gen., nov. sp. but it is estimated to have been less than l mm. Figs. 4F, G, E, 5B, 6, 7. The tube wall is 0.43 mm thick in one fragmentary spedmen and 0.28 mm in another. Platysolenites ('helical-shaped' specimens), Hamar 1967, The maximum diameter of the ioner space of 90-93, pl. l, fig. 4, 6, 14, pl. 2, fig. l (1, 2), 2. the se tubes is 0.65 and 0.58 mm respectively. Holotype.- PMO 98553. Description. -The fossil consists of a spirally Material. - PMO 70500, PMO 97819, PMO coiled tube. The initial portion (probably less 97821, PMO 97827, PMO 97830, PMO 97833, than one whorl in Iength) is missing in all other­ PMO 97844, PMO 97848, PMO 97849, PMO wise complete spedmens. The diameter of the 97853. About 14 more or less complete sped­ tube increases slow ly, if at all. The wall is thick mens including 3 external moulds, and about 12 and appears to be finely granular on its surface. fragments. The scanning electron microscope reveals p.m­ Occurrence. - Kunes, south of Laksefjorden sized apparently detrital quartz grains fused by (Fig. l, loe. 6) and three localities at eastern sheets of secondary silica. The tests are com­ Tana (see Føyn 1967, Addendum: 65-7 and pressed and their periphery is occasionally de­ 78-9). In shales of the Lower Breivik Formation, formed to an elliptical shape. The whorls are with Platysolenites. flattened and collapsed over the internal cavi ty, Diagnosis. - Genus and spedes: Small sili­ forming marginal elevations as in the straight ceous tubes, coiled in a Iow helicoidal spiral, tubes of Platysolenites. This must have preceded with 2-3 whorls which overlap more on the silicification. The agglutinated walls which prior to fossilization were collapsible or deformable

Fig. 4. A-D. Platysolenites antiquissimus. A - PMO 25105, are like those occurring in many 'arenaceous' Dorrovarre, Troms, x 9. B- PMO 97837, Nerasvarre, Tana, foraminifera. The outer surface shows more or x Il (note several rhombohedral dark hollows on tube surface, less faint transverse growth lines. They are interpreted as resulting from dissolved dolomite crystals). C­ straight or convex towards the aperture. The PMO 97835. Nerasvarre, Tana, x 5. D-PMO 97818, Kunes, x Il (a smooth transversely laminated tube). tubes are coiled trochospirally in a Iow cone, with the outer whorl overlapping the preceding Fig. 4. E-G. Spiroso/enites spira/is. E-PMO 97849, Moalasn­ one more on the base of the cone than on the junne, Tana, x 14 (spiral view). F - Holotype, PMO 98553, opposite side. Because the overlap is incomplete Vierccajokka, Tana, x 8 (umbilical view). G - PMO 97830, Nerasvarre, Tana, x 12 (spiral view). and because of the insignificant height of the spiral and the convexity of the whorls on the Fig. 4. H, J. Sabe/Jidites cambriensis. PMO 97815, Basavcce, base it is difficult to distinguish the two sides. In Tana (H = specimen l, J = specimen 6, on same rock piece) several specimens the coiling appears to be X 10. Photographed under alcohol by Mr. B. R. Elgvad, sinistral. The Iack of an initial portion of the tube Paleontologisk museum, Oslo. was observed in all well-preserved spedmens and external moulds. It can be explained by the Fig. 4. K. Tore/le/la /aevigata. PMO 25094, Dorrovarre, assumption that the initial wall, presumably Troms, x4. commendng with a proloculus, consisted of an Fig. 4. L-M. A/dane/la kunda. L - PMO 25111, x 12, M - organic substance and that formation of a thick, PMO 25109, x 15, Dorrovarre, Troms. preservable, tube by agglutination of sand grains started at a more advanced stage of growth. The Fig. 4. A-G, K-M. Whitened with ammonium chloride and photographed under a ring light illuminator by Dr. D. L. tubes are free in the shale matrix and were not Bruton, Paleontologisk museum, Oslo. attached to any mineral or other particles.

3- Geologisk Tidsskr. 1/79 34 S. Føyn & M. F. Glaessner NORSK GEOLOGISK TIDSSKRIFT l (1979) NORSK GEOLOGISK TIDSSKRIFT l (1979) Platysolenites and other animalfossils 35

Classification. - Hamar (1967: 91) believed sediments of the Bal tie Lower Cambrian. There that some tubes of Platysolenites 'are bent in to a they are clearly seen to be formed from aggluti­ spiral or helical shape (pl. l , figs. 4, 6, 14; pl. 2, nated sand grains. There is no reason to assume figs. 1-2)'. The specimens figured by Hamar that either Platysolenites or Spirosolenites were came from Kunes. The more abundant material originally layered calcareous shells like those of now available confirms Hamar's observation of the Serpulidae. While the shape of the tubes of similar wall structures in the straight and 'spiral the subfamily Spirorbinae Chamberlain 1919 is or helical' tubes (Fig. 5A, B) but not his conclu­ similar to that of Spirosolenites, the relations sion of generic or specific identity of the two between adjacent coils are variable in different forms. This conclusion is contradicted Spirorbinae and instead of the distinctive by the following facts. absence of tubes formed in early stages of Platysolenites is accompanied only at Kunes growth, some Spirorbis have a coiled and others and at the three eastern Tana localities by spi­ a thin, straight, or irregular 'apical tube' rally coiled tubes. (Wrigley 1950). The similarities of Platysolenites No transitions from straight to spiral forms or and Spirosolenites are such that both fossils vice versa have been observed. must be closely related. They were formed by The mode of coiling is generally regular in its agglutination of detrital grains, not by silicifica­ flatly trochospiral form and unequal overlap. tion of a calcareous shell. This excludes any Although the wall structure appears to have relationship to gastropods and to serpulid an­ been similar, taking account of diagenetic silicifi­ neJids. The close similarity of Platysolenites and cation, the wall of the spiral form is uniformly Bathysiphon indicates that the former represents thick while in the straight form there is a greater tubes of simple foraminifera. Spirosolen_ites variability in this character. None of these must be similarly placed. In modem classifica­ observations would be expected in intraspecific tion of the order Foraminiferida, a sharp distinc­ modifications. There is no reason for placing tion is made between the tubular, not enrolled, tubes with such basically different structures in Astrorhizidae and the coiled tubular Am­ the same genus, in the absence of transitional modiscidae. These possess a proloculus. No forms. known Foraminiferida show the combination of Hamar placed the spiral forms together with characters which distinguish Spirosolenites and Platysolenites in the family Serpulidae Savigny, which link it through Platysolenites with Bath­ 1818, of the Annelida Polychaeta. This family ysiphon (Astrorhizidae). At present the new includes worms with straight and spirally coiled genus may be placed in the superfamily Am­ tubes. All are calcareous and their microscopic modiscacea as 'incertae sedis'. wall structure shows the characteristic layering of worm tubes (Wrigley 1950, Schmidt 1951). The fossils here described are siliceous and the Aldanella kunda (Opik) preserved fine structure indicates agglutination Fig. 4L-M. from detrital quartz grains. This structure as well O 1926 Pleurotomaria ? kunda Opik, 45, fig. 2. O 1934 as the wall surface agrees with the observed 'Pieurotomaria' kunda, Strand, (unpublished manuscript). O character of the tube walls of Platysolenites. The 1967 Straparolina sp., Vogt., 31, 40. O 1973Aidanel/a kunda, Rozanov, 131, O 1977 Lendzion, 242. tubes of this genus are well preserved in the

Material. - 5 specimens, PMO 25109, PMO 25111, PMO 47172, PMO 47174, PMO 47176, Fig. 5. A - Platysolenites antiquissimus. PMO 97849/2, PMO 25110 is the counterpart of PMO 25109. Moalasnjunne, Tana. x 2 000 . Broken tube showing detrital grains embedded in layers of secondary silica. B - Spiroso/e­ Also possibly 1-2 poorly preserved specimens, nites spira/is. PMO 97848/3, Moalasnjunne, Tana. x 2 000 . PMO 47189-90. Broken tube showing detrital grains embedded in secondary Occurrence. - Dorrovarre, Troms area (Fig. l, silica. C - Cyclomedusa davidi Sprigg, Late Precambriam, loe. 3). According to Vogt in 'red and green Ediacara, South Australia. x0.95. Holotype of 'Madigania' annulata Sprigg (a subjective synonym), for comparison with shale' of Horizon D, 5.3 m above its base, with Kul/ingia concentrka (Fig. SA). Platysolenites antiquissimus, Torellella sp. and 'Hyolithes' sp. Probably also from Ruogooaive, 5. Fig. A-B comprises scanning electron microscope photo­ 20 km SSW, from the same Horizon D, 3 m graphs laken on an ETEC Autoscan in the University of Adelaide, Central Electron Optical Laboratory by Dr. K. above its base.

Bartusek. Remarks. - These fossils, found and listed by 36 S. Føyn & M. F. Glaessner NORSK GEOLOGISK TIDSSKRIFT l (1979) NORSK GEOLOGISK TIDSSKRIFT l (1979) Platysolenites and other animalfossils 37

Vogt, were identified first by J. Braastad who named them 'Straparolina', intended for Straparollina Billings, 1865. This name of an Ordovician genus was used by Billings and later by Walcott (1890: 617, pl. 74, figs. 12, 13) for Cambrian gastropods. At the same time Walcott figured as 'Pleurotomaria (Raphistoma) at­ tleborensis (Shaler & Foerste)' a specimen of 1 mm what became the type species of the genus

A/dane/la Vostokova, 1962. Vogt's fossils were Fig. 7. Spirosolenites spira/is. Diagrammatic reconstruction of studied in 1934 by Strand, whose manuscript broken test based on fragments from PMO 97848-9, Moalasn­ unfortunately remained unpublished at the time junne, Tana. Showing parts of two whorls. Spiral side upward. Matrix stippled. of his death in 1976. Strand referred them to 'Pleurotomaria' kunda Opik, 1926. Opik had queried the generic assignment of his species which was based on one specimen, probably an of other species. A. polonica Lendzion, 1977, internat mould. He recognised it as the oldest from the basal Cambrian of southeastern Poland known gastropod and later (1956) as congeneric is, on published evidence, not easily disting­ with Pleurotomaria attleborensis. After much of uishable from Opik's A. kunda, to which it is the Lower Cambrian fauna of Siberia bad been said to be closer than to the Siberian species. described and Opik's find repeated by Estonian geologists, Rozanov (1973) assigned this species to the genus Aldanella Vostokova, 1962 (type Sabellidites cambriensis species Shaler & Foer­ Cyrtolithes attleborensis Y ste, 1888) and found it 'surprisingly dose' to the anishevsky Fig. 4H,J. common Siberian A. rozanovi Missarzhevsky, 1966. The genus was placed in the family Sabellidites cambriensis Yanishevsky, 1926, 102, fig. 1-5, & Pelagiellidae Knight by Missarzhevsky and by 8-10; Hecker Ushakov, 1962, 451, pl. 3, fig. 10; Sokolov, 1967,202. fig. l( l); 1972,79,pl. l, fig. l a-d; 1973,204. Matthews & Missarzhevsky (1975), but in the

Sinuopeidae by Runnegar & Jell (1976), who Material. - About 15 fragments of tubes on a consider it as representing the first pleu­ bedding pl ane of a shale sample, PMO 97815. rotomarian gastropods. Yochelson (197 5) Locality. - Basavcce, eastem Tana (Fig. l, doubts, on mainly philosophical grouds, that the loe. 8. See Føyn 1967, Addendum). pelagiellids and Aldanella are mollusca. The Remarks. - This is the first record of Sabelli­ present material is not well enough preserved to dites from Scandinavia. These fossils are rep­ contribute substantially to the knowledge of the resented by flattened, black, carbonaceous morphology and systematics of this taxon. Com­ tubes, 0.45-1.5 mm wide. The lengths of the pression has almost obliterated some details of fragmentary tubes vary from about 5 to 12 mm. the shape and surface sculpture of the shell. Its Some are straight, some bent and some twisted. wall was thin and there are on it possible indica­ Transverse, straight ribs are clearly visible on tions of a few radial folds. The !argest diameter well preserved outer surfaces. Other areas seen ranges from 2-2.5 mm. The shape of this fossil is in low-angle incident light under the microscope eloser to A. kunda and A. rozanovi than to that show very fine transverse striation. Allowing for differences between preservation in rather silty

Fig. 6. Spirosolenites spira/is, Moalasnjunne, Tana. A- PMO hard shale and in the Blue Clay of Leningrad 97849/1,showing surface of part of two whorls. x 50. B -PMO where the first finds of the species were made, 97848/3, showing part of umbilical surface and transverse the characters of the tubes correspond closely, fracture through two whorls. x 60. C - same specimen, show­ and the measurements are within the limits ing transversely broken surface with sutures and outlines of infilled interior space. Walls and matrix are silicified. Sinusoi­ stated by Yanishevsky and Sokolov. Yanishev­ dal curvature of suture between whorls probably caused by sky ( 1926: l 02) described the surface as high ly re­ compaction. x 100. flective and either coarsely transversely grooved or smooth but showing under higher magnifica­ Fig. 6 comprises scanning electron microscope photographs taken on an ETEC Autoscan in the University of Adelaide tion also on smooth areas a fine transverse Central Electron Opitcal Laboratory by Dr. K. Bartusek. striation which does not always extend to the 38 NORSK GEOLOGISK TIDSSKRIFT l ( 1979)

A

Fig. 8. A - Kullingia con­ centrica. Holotype, SGU Type 22. NE slope of the mountain Luopakte, Tornetriisk. Photo: U.

Samuelsson. B - Kullingia aff. concentrica. Arumbera Sand­ stone, East of Laura Creek near Alice Springs, central Australia, XI.

margins. This, as well as hending and twisting Systematic position. - Sokolov described two can be observed on the present material, also the families and a number of genera of an Order occurrence of narrowed portions of the tubes. Sabelliditida which he placed in the 'Phylum Three of the tubes on the shale specimen show Pogonophora'. Until recently the Pogonophora irregular granules on their surface but this ap­ were considered as unrelated to the annelid pears to be the result of distortion of the thin worms but evidence is increasing (NØrrevang walls by sand grains in the matrix. 1975) of significant morphological relationships. NORSK GEOLOGISK TIDSSKRIFT l (1979) 39

Their taxonomic significance is still not fully partings or infilled cracks about 0.4 mm apart. elucidated. The question whether the Sabel­ Their exposed external moulds are smooth. liditida are ancient representatives of the They do not branch but they may overlap. Most Pogonophora, which is difficult to decide on the of them are straight but some have curved or evidence of the fossilized tubes, is therefore narrowing ends. Similar fossils occur at A ve­ losing some of its significance. According to vagge (PMO 47206-7) where some specimens are Sokolov, different genera represent them in the only 1/3 mm wide. It seems likely that these Late Precambrian and in the Lowest Cambrian fossils represent young specimens of Platysole­ of the East European and Siberian Platforms. nites which were covered with mud rather than with fossilizable agglutinated sand grains. They are accompanied by smaller, curved, limonitic, brown and yellow thread-like fossils, 0.15-0.25 Problematical tubular fossils mm wide which may be branching (PMO 47169- 70, Dorrovarre). They are probably plant re­ 'Hyolithes' sp. mains, possibly related to Tyrasotaenia Gni­ One specimen (PMO 25099) from Dorrovarre lovskaya, 1971, from the Vendian and Lower (Fig. l, loe. 3) was examined. It is about 20 mm Cambrian. None of these fossils can be Sabel­ long and widens from about l to 3 mm. It is liditidae because they are not graphitic, nor do flattened and only a small fragment of its shell is they show any transverse sculpture. They are preserved. Strand (1934, unpubl. ms.) considered not trails because they are short, with distinct that it has 'an elevated fold at each side' but this ends, and do not form networks or coherent feature may be eau sed by the complete flattening patterns. One problematic fossil figured by of the tube. No other surface sculpture is visible Hamar(1967, pl. l, fig. 2) from Halkkavarre as and the apertural margin is missing. In Strand's 'Platysolenites?' shows a very long (65 mm), opinion, this fossil resembles Orthotheca herme­ straight tube, l mm wide, without a wall and lini Holm, but lacks its transverse striation, and without transverse grooving. It is slightly bent a O. mickwitzi Opik, 1926, may be a related form. few mm from its end where it is overlain by an The angle between the sides of the tube, less irregularly curved tube with a pyritic covering. A than lO", is doser to that in Opik's species than bend in this tube gives the impression of a single in Moberg's (1908) 'Hyolithus sp.' from Y -shaped fossil but this is not confirmed by elose Luopakte. examination. Neither of these tubes can be as­ signed to Platysolenites. Tore/le/la laevigata (Linnarsson) Precambrian Strand (1934, unpub. ms.) recorded this species from Vogt's collections at Dorrovarre and Ruogooaive (Troms). One specimen, PMO 25094 Kullingia concentrica Glaessner, from Dorrovarre (Fig. 4K), was re-examined. It nov. gen., nov. sp. is about 15 mm long, with a maximum width of Fig. 8A. 1.2 mm, very slightly curved and with the Madigania annulata 1964, 29, 141, 5, (altered) shell not showing any surface sculpture Sprigg, Kulling. fig. 6; Kulling, 1972, 164, fig. 113, 114. but indicating a transverse structure where broken. The infilling is pyritic. Ho/otype.- SG U Type 22. Localities. -l. Mt. Luopakte, northern slope, south of the lake Tornetrask (Kulling 1972, 164, 'Problematica' fig. 110, Ill, 115), 'Middle sandstone of Hyolith­ Under this heading, Strand (1934, unpub. ms.) us Series'. 'All fossil remains collected are records from Vogt's collections a number of from the upper part of a roughly 2 m thick 'rusty trails' occurring with Platysolenites and greenish grey to light grey sequence of graded also some 'thread-like bodies'. Some of these, bedded sand y shales.' 2. 20 km south of fromDorrovarre(PM047161, PM047163, PMO Luopakte, 'Åppartjåkko', south of the lake 47171) are limonitic, brown and yellow tube Rautasjaure, (Kulling 1964, 29, pl. l), 25-28 m fillings without preserved outer walls. Some are above the contact with Archaean basement. 3. about i mm wide and show distinct transverse North of Tornetrask, about 7 km east of V akke- 40 NORSK GEOLOGISK TIDSSKRIFT l (1979)

jokk, 'in sandy shale with cyclic sedimentation, 22 km WSW of Alice Springs. According to the about l m below the Vakkejokk breccia' (Kulling finder's personal communication, the loose 1972, p. 164, fig. 127). specimen came from a bed of red sandstone with Diagnosis. -Genus and species: Flat disc with abundant trace fossils, about 250 m above the subcircular outline and regular, concentric, fine, base of the Arumbera Sandstone, 63 m below a evenly spaced ribs around a subcircular, possi­ 'glauconitic zone'. This 'zone' is probably the bly low conical centre measuring about l/6 of the base of the Lower Cambrian 'Boxhole Forma­ diameter of the disc. Few or no deep concentric tion' of Daily (former! y the middle member of furrows other than the grooves between the ribs, the Arumbera Sandstone, see Cowie & Glaess­ no radial sculpture. The distance between the ner 1975). The fossil came from about the same crests of the ribs in the media! part of the disc is horizon as Arumberia banksi Glaessner & Wal­ about 2 mm. ter, 1975, and Hallidaya brueri Wade. Further Comparison. - This fossil differs from Cyc­ intensive collecting in the Laura Creek area has lomedusa (syn.: Madigania Sprigg non so far failed to produce additional medusoid Whitley =Spriggia Southcott) in the absence of fossils. The fossil, best referred to as Kullingia irregularly spaced, concentric furrows and radial aff. concentrica, is incomplete because of break­ grooves, fromEdiacaria Sprigg (emended Wade, age. It shows a partial, smooth flange about 30 1972) in the presence of regular concentric ribs mm wide which may be due to decomposition of near the centre of the disc. It is possible that the the soft body before fossilization. The ribbing on identification of the Swedish specimens with the disc is concentric and slightly finer than in K. 'Madigania annulata' Sprigg was based not on concentrica, with a spacing of 7-10 ribs per lO the holotype (Fig. 5C, Sprigg 1949, pl. 16, fig. l) mm radius of the disc. It measures about 80 mm which was later placed in the synonymy of in diameter. The central portion, about 20 mm in Cyclomedusa by Glaessner & Wade (1%6) but diameter, is distorted. The concentric ribs are on one of the specimens which show concentric uniform in size, allowing for vagaries of preser­ ridges near the periphery and lack radial vation. The absence of any traces of radial grooves. This new genus of medusoids is dose to sculpture crossing the regular concentric ribs Cyclomedusa and like this genus (Wade 1972) it distinguishes this fossil from any of the could represent an early stage in the evolution of medusoids of the fauna from Ediacara, particu­ a hydrozoan (chondrophoran) float similar to larly Cyclomedusa and Ediacaria. that of the living Porpita. The ribbing of Kullin­ Ford(1963) has also recorded medusoid fossils gia resemb!es that of the chondrophoran occurring with Charnia and Charniodiscus as Ovatoscutum Glaessner & Wade, 1966 but the Cyclomedusa in the W oodhouse beds of Charn­ outline of the disc is circular. Concentric ribbing wood Forest, Leicestershire, England. They re­ which is sufficiently resistant to withstand oblit­ semble Kullingia in the absence of radial sculp­ eration by compaction of the embedding sedi­ ture but differ in the presence of several con­ ment is hardly compatible with the expansion­ centric rings, 10-15 mm wide, on the surface of contraction swimming mechanism of the hell of a the disc, separated by deeper furrows similar to typical medusa but not incompatible with the those found in several medusoids from Ediacara. functioning of a medusoid coelenterate lying, as some living forms do, with its exumbrellar side downward on the sea floor. A decision on its place in the system of the coelenterates must Biostratigraphic zones and their await the discovery of more complete sped­ ages mens. Biostratigraphic zones A single specimen (Fig. 8B) from the Arumb­ era Sandstone near Alice Springs in central The general and regional biostratigraphic zoning Australia resembles Kullingia concentrica. It of Lower Cambrian sediments and faunas is still was collected by G. K. Williams in the course of problematic (Palmer 1977) but the sequence of stratigraphic work on behalf of the Magellan Lower Cambrian zones in the region around the Petroleum Company and presented by the Com­ Baltic Shield is becoming clearer. The sequence pany to the Department of Geology and of fossils in the Late Precambrian - Cambrian Mineralogy of the University of Adelaide. It transition in northern Scandinavia can be related came from a creek 4.8 km east of Laura Creek, to a regional framework and calibrated in terms NORSK GEOLOGISK TIDSSKRIFT l (1979) 41

Tab/e l. Observed sequence of fossil occurrences in subdivi­ Formation (Bjørlykke et al. 1976) in which sions of the Dividal Group and equivalents in northern Skolithus, Monocraterion, and Diplocraterion Scandinavia. occur. The se trace fossils are representative of a facies (Seilacher l %7) which recurs frequently 4. Platyso/enites, Spirosolenites, Sabellidites, A/dane/la, etc. throughout at least the earlier half of Palaeozoic Middle Shale, D - 3. Trace fossils: Phycodes, 'proto- time. Their occurrence is significant for the age l-Rusophycus', Treptichnus• . of the Ringsaker Quartzite which will be discus­ Middle Sandstone, C - 2. Kullingia, possibly coeval with sed later. It would nonetheless be confusing to smaU trace fossils designate them formally as regional bio­ Lower Shale, B - l. Problematica and undescribed trace fossils stratigraphic zone fossils; they reappear in the sequence irrespective of stratigraphic position • 'Feather-stitch trail'. wherever the facies of Lower Cambrian strata changes to an indication of suitable local shal­ of a tentative general stratigraphic scale. With low-water conditions. few exceptions, only fossils known from the area The fossils named by Skjeseth as characteris­ under discussion will be considered here. tic of 'Zone laa1' were found only in the Flag­ · The following sequence of fossil occurrences stadelva section, 'in the upper part (The in the north is firmly based on field observations Brennsæter Formation) which consists mainly of by Kulling, Føyn, Banks and others. dark limestone beds, alternating with layers of The sequence from l to 2 was observed by shale' (Skjeseth 1963: 48). The lower part con­ Kulling in strata which he considered as lower sists of grey shale. This zone is said to be members of the 'Hyolithus Series', a term which 'missing at Ringsaker'. Unfossiliferous conglom­ is now obsolete. From the lower part of the erates 'might be considered as contemporaneous 'middle shale' (D), Kulling (1964: 33-4, 142) deposits because of their stratigraphic position' recorded Platysolenites antiquissimus, P. in the Bråstadelva and Lauselva sections. lontowa, Volborthella tenuis, and 'Hyolithus', The se scanty supporting data for the existence of but it is not known whether they were found a 'zone laa1' were questioned by Daily (1 972). together in the same bed. The precise occurr­ The stratigraphic sequence in Flagstadelva was ence of Platysolenites at Halkkavarre and Tana­ re-examined independently by K. BjØrlykke and fjorden was recorded in measured columns of by J. Bergstrom (with P. Ahlberg, G. Bylund, J. strata by Føyn (1%7) and Banks (1 970). Nystuen and G. Vidal) in 1977. They kindly Phycodes pedum first occurs in the lowest 3 m of permitted us to quote from their personal com­ the lower member of the Breivik Formation, munications. K. BjØrlykke reports that there are 140-1 50 m below Platysolenites (Banks 1970). many signs of tectonic deformation, slide planes, The conclusion from these observations is that and some thickness variations in the lowermost two distinct biostratigraphic zones can be rec­ shale along the strike, implying some squeezing ognised, an older one with Kullingia, followed but nothing to indicate repetition of strata. J. by a zone with Platysolenites. Small trace fossils Bergstrom concludes that the section is practi­ in the Stappogiedde Formation may or may not cally complete, including the contact with the be coeval with the Kullingia zone. The signific­ Ringsaker Quartzite and a continuous succes­ ant trace fossils in the Lower Breivik Formation sion of strata upward through the beds where locally precede but also occur together with Skjeseth found the trilobite, and further through Platysolenites. about l m of undisturbed strata to the coarser The local zoning in the south is still unclear. sediments with Mobergella. Weak folding in the Skjeseth (1 %3: 36, 48) distinguished in the Mjøsa lower part of the section is present, as would be region above the Ringsaker Quartzite and below expected, but there is no repetition. The trilobite the Holmia Shale three zones: closely resembles Holmia mobergi Bergstrom Zone la,B: Callavia n.sp., Volborthella tenuis from Skåne (Norretorp Formation) and is not Zone laa2: 'Discinella' ho/sti and Platysole­ Schmidtiellus ('Holmia') mickwitzi (Schmidt). nites antiquissimus Bergstrom mentions that the same appears to be Zone laa1: 'Holmia' cf. mickwitzi, Hyolithes true of the similar trilobite from Estonia de­ sp. scribed by Schindewolf. He concludes that there The fossiliferous sequence starts with the is a consistent pattern of biostratigraphic zones, Ringsaker Quartzite Member of the Vangsås thus: 42 NORSK GEOLOGISK TIDSSKRIFT l (1979)

Holmia kjeru/fi - Volborthel/a tenuis Platysolenites (see also Mardla et al. 1968). Of Holmia n.sp. (= 'Callavia - Volborthel/a tenuis particular interest is the occurrence of Aldanella n.sp.' of Skjeseth) together with the first Platysolenites in the Schmidtiellus mickwitzi and - Volborthel/a, Platyso/enites, Holmia mobergi Mobergella Lopiennik bore in southeastern Poland in the ?Trilobite fragment - Platyso/enites antiquissimus middle part of the Klimontov Stage, just below (Hardeberga Ss.) and the boundary between the Sabellidites and Rusophycus . Platysolenites zones (Lendzion 1977, fig. 2) . and that the Jocal occurrence of the probable Sabellidites occurs commonly throughout the Holmia mobergi about l m below Mobergella is Lontowa Beds, the main part of the 'Blue Clay' due to Jocal facies variations in the same sedi­ of Estonia and Leningrad and may extend into mentary packet and has no zonal significance. higher strata. The greatest abundance of In Skjeseth's opinion, Platysolenites, which is Platysolenites is in the Lontowa and the next reported from Stensviken in Ringsaker, repre­ younger unit, the Glebowo Beds (Birkis et al. sents the zone with M obergella. Skjeseth quotes 1972, Rozanov 1976). The latter are char­ Vogt (1924) but disagrees with his placing of the acterised by the occurrence of Mobergella. Platysolenites-bearing beds of Ringsaker, in Platysolenites extends above the top of the what became known as 'zone l3Ø'. There ap­ stratigraphic range of this fossil. Volborthella, pears to be little evidence for either of these though shown to occur together with the last interpretations. The ranges of Platysolenites and Mobergella, is considered by Rozanov (1976) as Volborthella overlap to some extent but they do confined to the Liikati and overlying Vergale not coincide. Beds in Estonia. Both together represent the Attempts to relate the palaeontological data widely recognised 'Holmia-Zone'. It appears from northern Scandinavia to the tentative zones from these comparisons that the first appear­ in the Lower Cambrian of the Mjøsa area are ances of Sabellidites -Platysolenites (abundant) assisted by comparison with the zonal scheme - Mobergella - Volborthella may be used as a now emerging from studies of the scarce surface sequence of biostratigraphic zones or, strictly, outcrops and the abundant subsurface data from biohorizons (Hedberg 1976). This requires cau­ the East European Platform. In eastern Poland tion because only Mobergella has a short range and adjoining regions, Aren et al. (1975) distin­ and its distribution is limited by environmental guish below the Holmia beds three zones: conditions. When sufficient palynological data 3. Mobergella become available, such as the work of Volkova 2. Platysolenites (1973) has provided for the East European l. Sabellidites Platform, the recognition of these zones may The Jower two zones (apparently first proposed become easier. by Kiryanov but criticised by Rozanov 1973) The lowest fauna! zone in northern correspond to the Mazowiecki Beds, the up­ Scandinavia is characterised by the occurrence permost to the Zawiszyn Beds, both together of the medusoid Kullingia. Although Kulling's representing the Klimontov Stage. Aren & identification of this fossil with a species from Lendzion (1974) show the occurrence of the the Late Precambrian of Ediacara, South Au­ nominate species in one bore where Sabellidites stralia, cannot be accepted, its similarity to one occurs in the Jower and Platysolenites in the from the Arumbera Sandstone in central Au­ upper half of this stage. Correlations across the stralia which contains Ediacara fossils in its East European Platform to Leningrad, Moscow, basal beds is significant. It is unlike any and the Ukraine (Rozanov 1973, fig. 128) show Cambrian fossil. It will be interesting to know generally the same zonal sequence of the first whether Kullingia occurs in the richly fossilifer­ appearance of the three named genera. More ous Late Precambrian strata recently found near recently, Bengtson ( 1977) reviewed the Arkhangelsk. The occurrence of simple trace stratigraphic position of the Mobergella zone fossils in the Stappogiedde Formation (Banks and confirmed its significance for correlation. 1970) is compatible with occurrences of such According to Rozanov (1976, fig. 9), Sabellidites fossils at Ediacara and on the East European and Platysolenites occur together in the Rovno Platform in the Late Precambrian. 'Horizon' but there are indications of the earliest The locally abundant occurrences of occurrence of Sabellidites preceding the first or Platysolenites in the Middle Shale (Unit D) of at !east the earliest abundant occurrence of the Dividal Group and in the Lower Breivik NORSK GEOLOGISK TIDSSKRIFT l (1979) 43

Formation support their correlation with occurr­ Aldanella appears to be confined to the lower ences of this fossil in the Mjøsa area. It is like! y two zones of the Tommotian Stage in Siberia and that the upper part of the range zone of to the Lontowa Beds ('Blue Clay of Kunda', Platysolenites is represented there; Mobergella Opik 1924, 1956) of the Baltic Stage of Estonia and locally trilobites occur at short stratigraphic (Sokolov 1958, 1965), and their equivalents in distances above the Ringsaker Quartzite Poland. The fauna of Unit D of the Dividal Member. Bergstrom (pers. comm.) identified a Group in Troms and its northern equivalent is trilobite closely resembling Holmia mobergi therefore likely to be of the same age, i.e. to from near the base of the shale section in Flag­ represent the lower part of the Platysolenites stadelva and suggested correlation with the range zone. When ranges of fossils in northern Norretorp Formation in Skåne and with the Skandinavia are compared with those from east trilobite-bearing interval in Estonia, which was of the Baltic Sea it should be remembered that placed by Schindewolf ( 1927) just above the to p palaeobiogeographic pathways existed not only of the 'Biue Clay' in the basal 'Eophyton Sand­ in the south but also between the northern and stone'. Opik (1956) indicated for the se trilobite eastern periphery of the Bal ti c Shield , extending occurrences a position in or above the upper by way of the Moscow Syneclise. levels of the Lontova Beds which are followed Volborthella has been reported from numer­ by the Liikati Beds 'with rare trilobite frag­ ous localities in Scandinavia (Martinsson 1974). ments'. The Liikati Beds (Mardla et al. 1968) It occurs in the Tornetrask area in the Middle are, however, now shown as beginning with a thin Shale with Platysolenites (Kulling 1964), but has conglomerate possibly indicating a hiatus and not been found in Finnmark. lts occurrences in containing trilobites and Volborthella. In sum­ the Mjøsa area were placed by Skjeseth (1963) in mary it can be said that the horizon with Holmia the 'zone 18/3' (Bråstad Shale), where it is ac­ mobergi and Schmidtiellus is placed generally companied by 'Callavia n.sp.' ( =Holmia n.sp. near the (disconformable) boundary between according to J. Bergstrom, pers. comm.). Where Lontowa and Liikati Beds in Estonia; this is also Volborthella occurs in the Middle Shale it indi­ the interval of overlap between the top of the cates the presence of equivalents of the Liikati range of Platysolenites and the base of that of or higher beds of Estonia and the lower Holmia Volborthella, and close to the horizon with Zone of Poland. Occurrences of trilobites show Mobergella outside Estonia (Giebovo Beds, the presence of higher zones of the Lower (and Rozanov 1973, fig. 128; Bengtson 1977: 13, 14) . Middle) Cambrian. Any part of this sequence An overlap or close proximity between the high­ can occur locally at a short stratigraphic distance est occurrence of Mobergella and the earliest above the Precambrian basement , due to regres­ trilobite of the Profallotaspis zone of the sions, denudation , non-deposition, or transgres­ Siberian Platform is also indicated by Rozanov sions in which occurrences of Monocraterion (1973, fig. 124, based on published, earlier, de­ and similar trace fossils are environmental indi­ tailed descriptions of the Tyusser Formation on cators rather than means of zoning and dating. the lower Lena River). The position of the Mobergella zone at the top of the Tommotian Age Stage in Siberia and the possible extension of its range just above it does not conflict with the The determination, by agreement, of the precise occurrence of Mobergella in the Flagstad River position of the base of the Cambrian in a bound­ section in the same sedimentary unit as a trilo­ ary stratotype section and the definition of bite but agrees with it. It also supports the view criteria by which its time equivalents can be that a hiatus exists between this unit and the recognised elsewhere are present tasks of a underlying Ringsaker Quartzite (Figs. 2 and 3). Working Group (Cowie & Rozanov 1975). Im­ However , the magnitude of this hiatus is not as portant interim decisions are that 'The "Edia­ great as shown by Rozanov (1973, fig. 142), who cara" type fauna should be considered Pre­ believes that it extends from the top of the cambrian' and 'The Olenellid (Fallotaspid) trilo­ Vendian to above the base of the Atdabanian bite faunas should be considered as Cambrian'. Stage to which the Liikati Beds in Estonia cor­ The fossiliferous successions between strata respond. containing these biostratigraphic markers are In contrast to the late Tommotian - ?earliest being studied with the intention of defining the Atdabanian genus Mobergella, the genus boundary somewhere within this interval. In 44 NORSK GEOLOGISK TIDSSKRIFT l (1979) accordance with this decision we consider, as of the Cambrian. The Varangian and Ediacaran Kulling had suggested, the zone with Kullingia Stages are by definition part of the Vendian as 'Ediacaran' (Late Precambrian, Harland & Series (Sokolov 1973). The succeeding Baltic Herod 1975) and the trilobite-bearing beds as Series is therefore part of the Cambrian System. Cambrian. We do not suggest that the base of the This is the (temporary) framework for regional Cambrian is necessarily marked by the first stratigraphic classification. The results of work appearance of trilobites or of any other group of now in progress should be awaited before pro­ shell-bearing metazoans, for reasons stated in posals for a still more precise positioning of the Cowie & Glaessner 1975. Briefly, these first base of the Cambrian in southern Norway and appearances are not everywhere contemporane­ Sweden are made. The occurrence of Skolithus ous, the first trilobites are not everywhere the and Diplocraterion in the Ringsaker Quartzite same, and the definition of the concept of skele­ which is a transgressive shallow-water deposit ton or shell so that its firstoccurrence becomes a (BjØrlykke et al. 1976: 285) does not agree with boundary marker is not easy (see Rozanov 1976: its traditional assignment to the Late Pre­ 53, footnote). The chronostratigraphic boundary cambrian which was based on lithostratigraphic at the beginning of Cambrian time does not arguments. Contrary to earlier published reports necessarily have a precise lithostratigraphic which have proved to be erroneous, these trace equivalent (Hedberg 1976). Rozanov has in fossils have never been found in demonstrably numerous publications insisted on considering Precambrian strata. The possibility of a the Tommotian, typified by a fossiliferous carbo­ Cambrian age for the Ringsaker Quartzite was nate sequence in Siberia, as the basal unit of the previously indicated by Norwegian geologists, Cambrian and has correlated with it the Rovno, who included the Eocambrian in the Cambrian, Lontowa, and Glebowo beds and their equival­ and by Daily (1972) and Rozanov (1976), who ents on the East-European Platform. Bengtson exclude the tillites from the Cambrian. The short (1977) has produced evidence for the correlation stratigraphic distance between the top of the of the Mobergella fauna with the uppermost upper (Moelv and Mortensnes) tillites and the Tommotian, and A/dane/la is confined to lower base of the Cambrian as accepted by us was beds of Tommotian age. The recognition of commented on by Banks et al. (l%9: 191-2), equivalents of the exact base of the Tommotian who calculated from comparisons of sedimenta­ is more problematic. Aren et al. (1975) have tion rates in these and younger strata that be­ proposed that either the top or the base of the tween 10 and 40 million years elapsed between Rovno 'Horizon', which contains the oldest the end of tillite deposition and the appearance Platysolenites antiquissimus and Sabellidites of the Breivik fauna. These tillites may well be cambriensis, should be the base of the younger than the latest Precambrian tillites in Cambrian. Sokolov (1974) has also indicated the other regions or continents, but there are good same possibilities for the placing of the base of biostratigraphic reasons why they should not be the Cambrian in eastern Europe. Unless and included in the Cambrian. until a decision is made by international agree­ ment on its stratotype and on its correlation which would place it above the Rovno 'Hori­ Conclusions zon', hence above the first occurrence of Platysolenites and Sabellidites in the Baltic­ The occurrence of Platysolenites makes it evi­ Scandinavian region, we consider that it is well dent that at !east the greater part of the Breivik placed below, i.e. at the base of the Rovno Formation and the corresponding unit D of the 'Horizon'. This is the base of the Baltic Stage as Dividal Group belongs to the Lower Cambrian. now understood by Sokolov (1974). It cor­ lf the trace fossii Phycodes pedum is accepted responds approximately to the base of the as being of Cambrian age, the lower limit of the Breivik Formation and its equivalents. The deci­ Cambrian has to be lowered to the base of the sion of the Working Group that Ediacaran faunas Breivik Formation. should be considered as Precambrian and that The fossils found by Kulling in the Middle biostratigraphic criteria should be the main basis sandstone formation (unit C) of the Dividal for the definition of the Precambrian/Cambrian Group at Tornetrask (identified by him as Sprig­ boundary precludes the use of the base of the gia annulata Southcott) are accepted as ele­ glacigene deposits of Varangian age as the base ments of the Ediacara fauna; this unit and the NORSK GEOLOGISK TIDSSKRIFT l (1979) 45 lower part of the Manndraperelv Member of the Banks, N. L. 1970: Trace fossils from the Late Precambrian and Lower Cambrian of Finnmark, Norway. Geo/. J. Spee. Stappogiedde Formation belongs to the Vendian Issue 3, 19--34. Series of the Upper Precambrian. Banks, N. L. 1973: Trace fossils in the Halkkavarre Section of Accordingly, the upper l 00 to 150 m of the the Divida) Group (?Late Precambrian - Lower Cambrian), Manndraperelv Member are considered as trans­ Finnmark. Nor. Geo/. Unders. 288, 1�. itional from Late Precambrian to Lower Banks, N. L., Edwards, M. B. , Geddes, W. P., Hobday, D. K. & Reading, H. G. 1971: Late Precambrian and Cambro­ Cambrian. Ordovician sedimentation in East Finnmark. Nor. Geo/. If the trace fossils Skolithos, Monocraterion Unders. 269, 197-236. and Diplocraterion are proofs of Cambrian age Banks, N. L., Edwards, M. B. & Reading, H. G. 1969: Written contribution in: Proc. Geo/. Soc. London No. 1657, 191- because they have nowhere been found in de­ 192. monstrably Precambrian strata, the Vangsås Bengtson, S. 1977: Aspects of problematic fossils in the Early Formation of the Mj øsa district, or at !east the Palaeozoic. Acta Univ. Upsaliensis 415, 71p. upper part of the Ringsaker Member, has to be Bergstrom, J. 1970: Rusophycus as an indication of early J. 3, included in the Lower Cambrian. Breaks are Cambrian age. Geo/. Spee. Issue 35-42. Bjørlykke, K., Elvsborg, A. & Høy, T. 1976: Late Pre­ probable above and below the Vangsås Forma­ cambrian sedimentation in the central Sparagmite Basin of tion. South Norway. Nor. Geo/. Tidsskr. 56, 233-290. Recent work around the area of the Baltic Birkis, A. P., Brangulis, A. P., Volkova, N. A. & Rozanov, A. Shield suggests a possible stratigraphic sequence Yu. 1972: New data on the stratigraphy of the Cambrian of Eastern Latvia. Doklady Akad. Nauk SSSR 204, 163-166. of biohorizons based on the first appearances of [In Russian]. (a) Sabellidites, (b) Platysolenites and A/dane/la, Cowie, J. W. & Glaessner, M. F. 1975: The Precambrian­ (c) Mobergella and (d) Volborthella. The distinc­ Cambrian boundary: A symposium. Earth Sei. Reviews Il, 209-251. tion between biohorizons (a) and (b) is still Cowie, J. & Rozanov, A. Yu. 1975: I. U.G.S./I.G.C.P. Pre­ uncertain beyond Poland and the east Baltic cambrian-Cambrian boundary working group in Normandy area. A/dane/la and Mobergella are confined to and Paris, 1974. Geo/. Mag. 112, 197-198. the Tommotian Stage in Siberia. This Daily, B. 1972: The base of the Cambrian and the first Cambrian faunas. Univ. Adelaide Centre for Precambrian biostratigraphic sequence and its correlative Researeh, Spee. Paper /, 13-42. value should be tested by further collecting at Eichwald, E. 1860: Lethaea Rossiea ou pateontologie de la known fossil localities and detailed stratigraphic Russie. 1657 p. mapping. Ford, T. 1963: The Pre-Cambrian fossils of Charnwood Fores!. Trans. Leies. Lit. Phil. Soe. 57, 57�2. Acknowledgements. The authors !hank the following for infor­ Føyn, S. 1967: Dividal-gruppen ('Hyolithus-sonen') i Finn­ mation and other valuable assistance: Dr. J. Bergstrøm, Uni­ mark og dens forhold til de eokambrisk-kambriske forma­ versity of Lund, Sweden; Professor K. BjØrlykke, University sjoner. Nor. Geo/. Vnders. 249, 84 pp. of Bergen, Norway; Dr. D. L. Bruton and Mr. B. R. Elgvad, Glaessner, M. F. 1963: Major trends in the evolution of the Paleontologisk Museum, Oslo, Norway; Dosent S. Laufeld, Foraminifera, 9--24. In Koenigswald, G. H. R. von (ed.), Geological Survey of Sweden, Stockholm; Mr. R. Barrett, Evolutionary Trends in Foraminifera. Elsevier, Amsterdam. photographer, Department of Geology, University of Glaessner, M. F. 1978: The oldest Foraminifera. Australia, Adelaide; Mr. T. Sætre, draughtsman, Geological Survey of Bureau Min. Res. Bull. 192, 61�5. Norway, Oslo. Glaessner, M. F. & Wade, M. 1966: The Late Precambrian fossils from Ediacara, South Australia. Palaeontology 9, 599--628. Glaessner, M. F. & Walter, M. R. 1975: New Precambrian fossils from the Arumbera Sandstone, Northern Territory, International Geological Correlation Pro­ Australia. Aleheringa /, 11-28. gramme Gnilovskaya, M. B. 1971: The most ancient Vendian water Contribution to Project 29 - Precambrian­ plants of the Russian platform (Late Precambrian). Pa/eont. IU S Cambrian Boundary. Zhurnal, 3, 10 1-107. [In Russian]. UNES O l Hamar, G. 1967. Platysolenites antiquissimus Eichw. (Ver­ mes) from the Lower Cambrian of northern Norway. Nor. Geo/. Vnders. 249, 87-95. References Harland, W. B. & Herod, K. N. 1975: Glaciations in time. Geo/. J. Spee. Issue 6, 189--216. Aren, B., Keller, B., Rozanov, A. & Urbanek, A. 1975: Hecker, R. F. & Ushakov, P. V. 1962: Vermes. In Orlov, Polish-Soviet Symposium on the problem 'Cambrian--Pre­ Yu.A. (ed.), Osnovy Paleonto/ogii. Akad. Nauk SSSR, cambrian Boundary'. Izv. Acad. Sei. USSR, Ser. Geo/. 4, Moscow. [In Russian]. 134-137. [In Russian. ] Hedberg, H. D. (ed.) 1976: International Stratigraphic Guide. Aren, B. & Lendzion, K. 1974: Organic remains at the Wiley, New York-London. 200 p. Vendian...Cambrian boundary in the Platform sediments in Holtedahl, O. 1918: Bidrag til Finmarkens geologi. Nor. Geo/. Poland. Bull. Acad. Polon. Sei. , Ser. Sei. de la Terre, 22, Unders. 84, 314 p. 49--53. 46 NORSK GEOLOGISK TIDSSKRIFT l (1979)

HoweU, B. F. 1%2: Worms. In Moore, R. C. (ed.), Treatise on Seilacher, A. l %7: Bathymetry of trace fossils. Marine Geo/., Invertebrate Pa/eonto/ogy, Pt. W. Geol. Soc. Amer. 5, 413-428. KuUing, O. 1964: Oversikt over Norrbottensfjallens Skjeseth, S. 1%3: Contribution to the geology of the Mjøsa Kaledonberggrund. Sveriges Geo/. Unders. Ser. Ba 19, 166 district and the classical sparagmite area in southern Nor­ p. way. Nor. Geo/. Unders. 220, 126 p. KuUing, O. 1972: The Swedish Caledonides, 147-302. In Sokolov, B. S. 1958: The problem of the lower boundary of the Strand, T. & Kulling, 0.: Scandinavian Ca/edonides. Wiley­ Palaeozoic and the oldest sediments of the Pre-Sinian Interscience, London-New York. platforms of Eurasia. Trudy VNIGRI 126, 5-f>? [In Russian]. Lendzion, K. 1977. First gastropod fauna from the Klimonto­ Sokolov, B. S. 1%5: The oldest deposits of the early Cambrian vian Stage (Lower Cambrian) of the South-Eastem Poland. and the sabelliditids, 78-91. In All-Union Symposium on the Kwarta/nik Geo/. 21, 239-243. Palaeontology of the Precambrian. Abstracts. Novosibirsk. Mardla, A., Mens, K., Kajak, K., Kala, E. & Erisalu, E. 1%8: [In Russian ]. On the stratigraphy of the Cambrian strata in Estonia. 22-32. Sokolov, B. S. 1967: The oldest Pogonophora. Doklady Akad. In Grigelis, A. (ed.) Stratigraphy of the Ba/tie Lower Nauk SSSR, 117, 201-204. [In Russian]. Paleozoic and its correlation with other areas. 'Mintis', Sokolov, B. S. 1972: Vendian and early Cambrian Sabelliditida Vilnius. (Pogonophora) of the USSR. Proc. !PV, 23 lnt. Geo/. Congr Martinsson, A. 1974: The Cambrian of Norden, 185-283. In /968, 79-86. Holland, C. H. (ed.) Cambrian of the British Isles, Norden Sokolov, B. S. 1973: Vendian of Northern Eurasia. Amer. and Spitsbergen. Wiley, London-New York. Assoc. Petroleum Geo/. Mem. 19, 204-218. Matthews, S. C. & Missarzhevsky, V. V. 1975: Small shelly Sokolov, B. S. 1974: Problem of Precambrian/Cambrian fossils of late Precambrian and earl y Cambrian age: a review boundary. Geo/. & Geophys., Acad. Sei. USSR Siberian of recent work. J. geo/. Soc. 131, 289-304. Div., No. 2, 3-29. Moberg, J. C. 1908: Bidrag til kiinnedomen om de kambriske Sprigg, R. C. 1949: Early Cambrian 'jellyfishes' of Ediacara, lagren vid Tornetrask. Sveriges Geo/. Unders. ser. C 212, 30 South Australia and Mount John, Kimberley District, West­ p. ern Australia. Trans. Roy. Soc. S. Australia 73, 72-99. Nørrevang, A. (ed.) 1975: The phylogeny and systematic Strand, T. 1934: Unpublished manuscript on palaeontological position of the Pogonophora. Zeitschr. f zool. Syst. und description of Vogt's fossils from Lappmark. Deposited in Evolutionsforsch. Sonderheft. Geologisk institutt, NTH, Universitetet i Trondheim, and Opik, A. 1926: Uber den estlandischen Blauen Ton. copy in Palaeontologisk Museum, Oslo. Sitzungsber. Naturforsch. Ges. Univ. Tartu 33, 39-47. Vidal, G. 1976 a: Late Precambrian microfossils from the Opik, A. 1956: Cambrian (Lower Cambrian) of Estonia. XX VisingsØ beds, South Sweden. Fossi/s and Strata 9, 57 p. Congr. geo/. intern. Mexico. El sistema Cambrico, su Vida!, G. 1%7 b: Late Precambrian acritarchs from the paleogeografia y el problema de su base. Part l, 97-126. Eleonore Bay Group and Tillite Group in East Greenland. Palmer, A. R. 1977. Biostratigraphy of the Cambrian System. Grønlands Geo/. Unders., Rapport Nr. 78, 19 p. Ann. Rev. Earth Planet. Sei. 5, 13-33. Vogt, T. 1918: Geologiske studier langs den Østlige del av Rozanov, A. Yu. 1973: Regularities in the morphological fjellkjeden i Tromsø amt. Nor. Geo/. Tidsskr. 4, 260-266. evolution of regular Archaeocyathean and the problems of Vogt, T. 1924: Om forholdet mellem sparagmit systemet og det Lower Cambrian Stage division. Trans. Geo/. Inst. Acad. marine underkambrium ved Mjøsen. Nor. Geo/. Tidsskr. 7, Sei. USSR, 241, 164 p. [In Russian]. 281-384. Rozanov, A. Yu. 1976: The Precambrian-Cambrian boundary, Vogt, T. 1%7: Fjellkjedestudier i den Østlige del av Troms. 31-53. In: Keller, B. M. (ed.) Boundaries of Geo/ogica/ Nor. Geo/. Unders. 248, 60 p. Systems. Nauka, Moscow [In Russian]. Volkova, N. A. 1973: Acritarchs and correlation of Vendian Rozanov, A. Yu. & Missarzhevsky, V. V. 1966: Bio­ and Cambrian of the Western part of the Russian Platform. stratigraphy and fauna of Lower Cambrian Horizons. Trans. Soviet Geo/. No. 4, 48-f>2. [In Russian]. Geo/. Inst. Acad. Sei. USSR, 148, 126 p. [In Russian]. Wade, M. 1972: Hydrozoa and Scyphozoa and other Runnegar, B. & Jell, P. A. 1976: Australian Middle Cambrian medusoids from the Precambrian Ediacara fauna, South molluscs and their bearing on early molluscan evolution. Australia. Pa/aeonto/ogy 15, 197-225. Alcheringa /, 109-138. Walcott, C. O. 1890: The fauna of the Lower Cambrian or Schindewolf, O. H. 1927: Eine Neue Reconstruktion von Olenellus zone. lOth Ann. Rept. U. S. Geo/. Survey. Holmia mickwitzi Schm. (Fam. Mesonacidae Walc.) aus Wrigley, A. 1950: The difference between the calcareous tubes dem .Unterkambrium Estlands. Zeitschr. deutsche Geo/. of vermetids and serpulids. Journ. Conchyliol. 90, 118-121. Ges. 79, Monatsber. 112-120. Yanishevsky, M. 1926: Sur les restes de Tubicola de l'argile Schmidt, F. 1888: Ober eine neuentdeckte unterkambrische cambrien. Yezheg. Russk. Paleont. Obshch. 4, (1922-24), Fauna in Estland. Mem. Acad. Imp. Sei. St. Petersburg, 99-111. [In Russian). ser. 7, 36, 27 p. Yochelson, E. L. 1975. Discussion of early Cambrian 'mol­ Schmidt, W. J. 1951: Die Unterscheidung der Rohren von luscs'.J. geo/. Soc. /3/, 661-2. Scaphopoda, Vermetidae und Serpulidae mittels mikro­ skopiscer Methoden. Mikroskopie, 6, 373-381.