56. 01 6: 591 .52:55 1.?3 3.33 (4?4 ) Y).IK
LATE SILURIAN SHALLOW AND DEEP WATER CONODONTS OF THE EAST BALTIC
V. Viira
The present paper deals wi th the zonation of the East Ba ltic Upper Silurian cona dants and their facies dependence . A large number of samples were studied for to ·char acterize all facies belts from near- shore up to basin one . They come from 7 borings of Saaremaa tOhesaare , Kaugatuma , Kingissepa , Sakla) and North-We st Latvia (Kolka- 5 4,
Ventspils , Pavilosta} and also from mare than 30 localities of Saaremaa (Fiq . 1) . Pub- lished information is available only on conodonts from Kolka- 4 (raanHTe, Yn&eT, 1974 ) and ühesaare boring (BHRpa , 1977) , on the Upper Silurian spathoqnathodians (BHRpa , 1982 a) , and the apparatus Ctenognathodus murahisoni (BKRpa 1982 0 ) .
Fig . 1 L afvia Location map of outcrops (quadrangles) and borings (circles) . Explanation of locality numbers see in Fig . 3.
General distribution
Ludlow and Downtan conodont faunas show high abundances and rather low di.versity. They are characterized by bar and blade elements , .,,hereas platf0rm elemer>t:s ::ppear to be of very limited distribution . Carbonate deposits of the shelf area ccntain the rich est fauna where the prevalence of multielement genera Ozarkodina and Ou l odus is typical of the given region . The Ludlow part of the section is rich in the longranging appara-
79 tuses Ozarkodina aonf·Zuens, 0. e. exaavata� Ou Z odus siZuriaus. In the East Baltic they appear gradually beginning wi th the Lower Wenlock but the largest gatherings occur just in the Ludlow . The Downton contains bestde s 0. aonfZuens also abundant 0. s. eosteinhor nensi s and Ou Z. e 1-egans. On Gotland different Ozarkodina and Ou 1-odus '(=Hindeode Ha and Ligonodina) also occur nearly in the same quanti ty as in Estonia ( Jeppson , 1�69, 1972, 1974) .
Two distinct changes are observable in s tratigraphic range of the Upper Silurian conodonts of the northern East Baltic . The first is expressed by replacement of the
Upper Wenlock sha llow water Ctenognathodus murahisoni association with a rich Ludlow fauna contain ing o. aonf�uens, 0. e. exaavata and Ou'l. si'luriaus. These apparatuses are known a lready from the underlying Wenlock deposits but in specific condition of the Rootsiküla time they were rare or lacking . The second change is more dist�nct . It is defined by the appearance of conodon ts of the eosteinhornensis Zone. Besides the index species o. s. eosteinhornensis, OuZ. eZegans ma�es its first appearance on this level . The named two taxa in association with 0. aonfZuens form the rich Downtan fauna . All three apparatuses occur up to the uppermost beds of the Silurian .
Taxonomic notes
In the northern East Baltic at the present stage of study the fol lowing appara tuses. and their companent elements have been identified .
1. Ozarkodina exaavata exaavata (Branson et Mehl) : Spathognathodus ina 'linatus inaZinatus (Rhodes ), Ozarkodina media Walli ser , Neoprioniodus e xaav atus (Branson et Mehl) ,
Hindeode Z. Z a equidentata Rhodes ,
P'Leatospathodus e x tensus- Rhodes ,
Triahonode Z'la exaavata (Branson et Mehl) . The apparatus ranges from the Jaani Stage (Lower Wenlock) into the Kuressaare Stage (uppermost Ludlow) . 2. Ozarkodina aonfZuens (Branson et Mehl) : Spathognathodus primus (Branson et Mehl) , Ozarkodina typiaa Branson et Mehl , Neoprioniodus bicurvatus (Branson et Mehl) , Hindeode 'l'la aonfZuens (Branson et Mehl) ,
PZ.eatospathodus- f Zexu o sus Branson et Mehl ,
Triahono de ZZa symmetriaa (Branson et Mehl) . Most characteristic part of the apparatus isits spathognathodontan element S. pri mus . On the basis of morphologi cal differences in S. primus 5 morphotypes (Klapper ,
Murphy , 1974) and three subspecies ( Helfr ich , 1975) have been establi shed . In the nprth ern East Baltic 6 chronological subspecies : S. primus buaerus (Wenlock), S. primus den sidentatus (Uppermost Wenloc� , S. primus retroversus (Uppermost Wenlock) , S. primus aornidentatus (Ludlow) , S. primus ambiquus (uppermost Ludlow ) and s. primus n;asutus (Downton ) have been propesed (BHäpa , 1982 a) . 0. aonfZuens makes its first appearance in the lowermest beds of the Jaaqarahu Stage (Wenlock) and is present up to the end of the Silurian . 3. Ozarkodina steinhornensis eosteinhornensis (Walliser) :
Sp a thognathodus steinhornensis eosteinhorn�nsis Walliser , Ozarkodina typiaa dena kmanni Zieg ler ,
Neoprioniodus arisaigensis Legault, H indeode'll a p risaiZ. Z a Stauffer ,
80 P'leetospathodu:-s a'lte rnatus Wa lliser , Triehonode lla symmetriea (Branson et Mehl) .
The characteristic element is S. s. eosteinhornensis. in wh ich 4 varieties are dis tinguished (B:-itl:pa , 1982 a) . The apparatus occurs in the Kuressaare , Kaugatuma and Ohe saare Stages .
4. Ozarkodina sp . S : Neoprioniodus ? sp . S Viira, 1977, Ligonodina sp. S Viira, 1977, Triehonode lla sp . S Viira, 1977 .
Undescribed apparatus, evidently containing six robust elements . The appara.tus is restricted to the lower half öf the Paadla Stage. 5. Ou'lodus si'lurieus (Branson et Mehl) : Lonehodina wa lliseri Ziegler , Lonehodina greilingi Walliser , Neoprioniodus mu 'ltiformis Wa lliser , Ligonodina siluriea Branson et Mehl, Triehonode ZZa ineonstans Walliser .
The complete apparatus is illustrated by Chlupa6 , Kri � und Schönlaub (1980, Table 17, Fig . 20) . In the East Baltic Silurian it ranges from the Jaagarahu Stage up to the uppermost beds of the Paadla Stage . 6, Oul odus elegans (Walliser) : Lonehodina detorta Walliser , Ozarkodina ortuformis Wal liser , Neoprioniodus wi Z Ziamsi Legault, Ligonodina e'legans Walliser, Triehonode ZZa ineonstans Walliser . The apparatus occurs in the Kuressaare , Kaugatuma and ühesaare Stages . 7. Ctenognat hodus murehisoni (Pander) : Spathognathodus murehisoni (Pander) , Ligonodina sp. n. L Viira, 1977,
Lonehodina ? sp . n. N Viira , 1977 , Triehonode 'lla sp. n. V Viira, 1977 . The apparatus is described and illustrated in the paper on the Upper Wenlock shal low water conodonts (BHt!:pa , 1982 0) . e. murehisoni is a guide fossil for the Rootsiküla Formation . Besides the above named ones elements of the following apparatuses have been found : Diatomadus dubius (Rhodes ), Pe lekysgnathus dubius Jeppsson , Koekelel'la variabi'lis Wal liser , Po lygnathoides silunieus Branson et Mehl . Names of conodonts interpreted by formal taxonomy are g iven in inverted commas.
Associations
In the East Baltic Wenlock and Upper Silurian the environmental types of conodonts are distinguished : lagoonal , shoal-shelf and slope ones . Terms come from facies belts of the Silurian Paleebaltic Basin (HecTop , 3t!:HacTo , 1977) . From thesh allow inshore t.owards the continental slope the assoc iations are as follows : (1) Ctenognathodus, (2 ) Oza:t'ko- dina and Ou lodus, (3) KoekeleHa and Po lygnathoides.
Lagoonal type is represented by Ctenognat hodus association known from the Upper Wenlock so far . Besides lagoon it occurs also in the transitional area to the shoal
81 belt (BuApa, 1982 6) . Ty pical representative of this association is Ct enognathodus mu� chisoni. other conodonts are rare . 0. confluan s with a spathognathodontan element "S . " pPimus retrovRrsus occurs sometimes .
Shoal-shelf type of conodonts is mostly represented by Ozarkodina and Ou lodus . These two mu ltielement genera are distributed in the whole mentioned area . The shoal belt is rich in 0. confluens association , wh ich is rather commol"! in the open shelf as wel l. It occurs in detritic , nodular and clayey limestones . The 0. e. exaavata associa tion is mere characteristic of the open shelf belt of Ludlow age but' i t is found &lso in the shoa] belt . However , 0. e excavata does uot occur ih Downtori and its ecolagiea l niche is occup1.ed by the 0. s. eosteinhornensis associn.t::.on . These tv10 associations are characterized by a wider facies affiliation as compared with the 0. confluens associa tion and they may occur also in clays and marls of the slope belt.
Conodonts of the multielement genus Oulodus. being frequent in the shoal and open
shelf belts , are mnstly represented by species Ou l. siluric�s (Ludlow) and Ou l. elegans
(Downton) . Ou l. siluri·cus ha s nearly the same ecolagieal positian as 0. confluens . O• Koeke lella variabilia and �o lygnathoides siluricus in Lud low . Zonation The abundance of conodonts deereases frvm the shallow part of the basin towards the open sea . Such a situation is especially characteristic of Ludlow conodonts . Simul taneously with decreasing of their number a taxonomic change takes place : in offshore facies platform conodonts appear . Therefore we have presented two zonal s�hemes : one for shallow and the other for deeper water sediments (Table) . Ta O/e Norfhern Easf Balfic Upper Siluri;m conodanf zanes ." ..... Regianai sfrafigraphic SHEL F AREA DAS/N AREA ii: scheme � Zane Sub z on e Zane remscheidensis OHES AARE :<: - -- - l:::l -� - -- f- ."� canadensis :<: LÕO � KAUBATUHA r------l:::l "'f: eosfeinhornensis ÄI6U -e:: e s e ne sis 1:::1 · !::: o f in hor n s. str. � 1------KUDJAPE "' "' KURESSAARE "' aff scanica � TA HULA t::J .Belodus" sp. ------..... UDUVERE D. dubius ------1:::1 l cu :::::, HIMM! STE si uri s PA ADLA Dzarkodina sp. S- ...... ------n l cornidenfafus SA UVERE a co fuens - - - -- SDE51NINA V I U Cfenognafhodus � ES K '-> ROOTSIKÜLA e s i a i a t::J KUUSNÕHHE mur hi un s g ff ..... :<: VIITA ...... � 82 Zones with aagitta, eosteinhornensis and 6iluri�us were established in the Carnic AlfS by ü. WaTliser (1964), later on they are recognized in many parts of the world. üther Upper Silurian zones o:" the northern East Baltic are local. They are assemblage zones presumably. Subzones of the eosteinhOI'Yiens-is Zon·e are based on the replacement of different "Srathognathodus" s. eosteinhornens-is morphotypes. An important guide fossil is "8pathognathedus11 .aff. snojdr·i. Among conoQoats i den tified as "S. " aff. sna,jdri two morphological types sirr.ilar �o 118, " snajdri and "S. " crispus are established. In literature both they are interpreted as zonal ones whereas "S, " ci'isp!. Helfrict-, 1975; Chlupac , K r i z , Schönlaub, 1980). In our ma�e:::-ial there is no clear suc cessian of the above spe�ies. E.g. in 15 kg of sample dissolved from Karala locality among hundred specimen� of "S. " aff. snajdri both element types occur1ed. Thus for as certain1ng the positian of "S. " snajdri and "S. " crispus we mark our forms in the open nome,nclature. "S. " aff. snajdri ranges from the lower part of the Paadla Stage up to lowermest Kaugatuma Stage. It has been identified in all studied sections of northern East Baltic, including more offshore ones, but also in a number ef localities of the Saaremaa (Fig. 2, 3}. The lower limit of the "S. " aff. snajdri range is recognized in the studied bor ings on the following levels: Sakla 33.2 m, Kingissep& 39.2 m, ühesaare 113.3 m, Kolka 289.8 m, Ventspils 464.2 m, Pavilosta 622.7 m. Relative to the lower boundary of the Paadla Stage in above sections the species appears step by step bigher towards the central part of the bas�n. The upper limit of the "S. " aff. snajdri range is more uni form. The lates� specimens occur in the lowermest part of the Äigu �eds: Kaugatuma 28.9 m, ühesaare 61.2 m, Kolka 253.6 m, Ventspils 406.0 m, Pavilosta 604.0 m. Shelf zones Ctenegnathedus m�rchiseni Zone The base of the murchiseni Zone (BH�pa, 1982 6) is defined by the appearance of C. murchiseni. The fauna of the zone is dominated by index-species. 0. cenfluens is repre sented by subspecies with a spathognathodontan element "S. " primus retreversus. 0. sa gitta bohemica and n. e. excavata are rare. The zone �orresponds to the Rootsikula Formation (excl. lowermest part). The stratatype for the zone is Vesiku outcrop. Ozarkedina sp. S - 0. confluens cernidentatus Zone The zone is defined primarily on the ranges of the Ozarked-ina sp. S apparatus. The base of the zone is determined by the first appearance of Ozarkedina sp. S or - 0. cen fluens cernidentatus. The latter subspecies appears in Fig. 2 given borings on levels: ühesaare 118.0 m, Kaugatuma 81.2 m, Kingissepa 43.3 m, Sakla 34.1 m, Kolka 304.2 m. The zone is rich in two nominate species. 0. e. excavata and Oul. silur•icus are frequent. "S. " aff. snajdri first appears in this zone. The zone covers the Sauvere and Himmiste Beds and the lower part of the Torgu Formation. It may be distinguished in the near-shore and shelf areas only. The strata type of the zone is Roopa cliff. Distemodus dubius - "Beledus" sp. Zone The zone is characterized by the occurrence of Distemodus dubius, Pelekysgnathus dubius and "Beledus" sp. Its lower boundary is marked by the first appearance of D. dubius or "Beledus" sp., in case the former is lacking. The base of the zone lies in borings (Fig. 2) as follows: ühesaare 106.5 m, Kaugatuma 57.5 m, Kingissepa 35.0 �. Sakla 19.9 m, Kolka 294.6 m. 83 P.A.VIU JS TA VENTSPILS I • • • 1 �saa i "": I I I * ! i ., ,1 ' i I I � l .. I I :lõ I KOLKA � ! 55 � 0 1 jj:fi . ! r Zones SubzoHes -\ I 1& OHESA ARE I I I K.!b I I ·; Ii Il remscll6idenGis I � 60C I 1 1 I li , I I I ------I I . KAUBATUHA I I canadensis � -t: : . I !;, K/N6/SSEPA � BDshinhor I � nl!nsis s. str. &50 SAKLA ilff, sctmica I I KJal I • • 0.dubius - BBIDdUI! lp. ��.L- _ _ I I_ Q) Dz•rkmiiM sp.S-0. con 1oo .... fluen8 comidenfBfuS I 6111! 6 -� I C.murcltisoni •• t I :.; I .,-� � � .., I "1ll! .:!Ü'- .l;! -� -I �?:�!:nr -�� 1 1 Fig . . Correlation 2 of the Upper Silurian boring sections in the northern East Baltic by conodonts . Stratigraphical subdivisions of the Ventspils core : s dhNv - Nova Beds of the Dubysa Formation , s pgEn - Engure Member , 2 2 s pgMt - Mituva Beds , s pgVn - 2 Ventspils Beds , all three the Pagegiai Formation , s mnSl - Silale Beds and 2 2 s mnVr - Varniai Beds of the Minija Formation , s jrGrd 2 - Girdziai Beds , s jrVnz - Venz ova Beds and s jrGrz 2 2 2 Gärzde Beds of the Jura Formation . Loode Klf Dhesaare I � Lõo 27 Kaugafuma 26 lügu 1 25 KJ b Aijp2 �:rr ___ n /'1urafsi 3 24 I Vaivere 23 I f-- Va tsküla 22 I llpla 1 21 llp la 2 K5a Loode Tammik ZQ 1 K1�issepa 19 � � � Ku rjape 18 i Laadjala 17 � �I � f-- Unimiie 16 I Katri 1 15 I I 2 � Katri I 1 Jlf Udu vere I Udu vere 2 Kara /a 13 I Piihk/a 1 12 Pähk/a 2 iI Ans1 11 I Kz Himmisfe 10 I Kõrkküla g I Roo 8 pa I Rli"vmägi 7 Afla li I I Kärla 5 � Pa ad/a 4 ) I Kog uta J ' � I z � � Kandia I Sauvere 1 � � � ! 0 Fig . 3. Distribution of se lected conodonts in the Upper Silurian localities of Saaremaa . Abundsnces o rart> • common ö 11/x!ndanf A verg a6vntlllnf Besides the two index species the zone contains P. dubius, 0. confluens cornidenta tus, 0. e. excavata, Ou l. siluricus . All these conodonts disappear at the upper bound ary . D. dubius - "Be lodus" sp . Zone occupies the Uduvere Beds and upper part of the Torgu Forrnation . The zone has been deterrnined in the sections of the shelf area . The stratatype of the zone is Unirnae abandoned quarry . Ozarkodina steinhornensis eosteinhornensis Zone In the East Baltic the lower boundary is well distinguished by the appearance of nurnerous specirnens of all zonal apparatus elernents and those of usually accornpanying it Ou l. elega ns. The third , rnore frequent apparatus is 0. confluens with two spathognatho dontan elernents on subspecies level "S . " primus ambiquus and "S . " primus nasutus . Be sides thern there occur "S . " aff . snajdri (inthe lower subzone ) and undescribed new appa ratus of Ozarkodina (at least two taxa) . The eosteinhornensis Zone re aches the upperrnost beds of the Silurian section of the northern East Baltic . In the East Baltic basin it has been identified in all the 85 studied sections . However , the investigations revealed a difference in the frequency of occurrence : while in relatively shallow water sections (Kaugatuma , Ohesaare , Kolka) it is common and found almost in all samples, in places even in great abundances , then in deeper water deposits (Pavilosta) it is rare and occurs , by no means , in all samples . O:o the basis of the stratigraphical distribution of morphotypes of the "S. 11 s. eosteinhornensis element subzones are distinguished in the shelf deposits �BHtl:pa , 1982 a) . However , as differences between morphotypes have transitional character the limits of subzones are not always clear . Ozarkodina s. eosteinhornensis aff . 0. s. scanica Subtone . The lower boundary coincides with that of the eosteinhornensis Zane . The sub zone corresponds to the inter val of the occurrence of the earliest morphotype . By its morphology the spathognatho dontan element of 0. s. eosteinhornensis aff. 0. s. scanica is similar to that of Hin deodeZZa steinhornensis scanica apparatus described by L. Jeppsson (1974) from the Oved . Ramsgsa Group at Bjäsjölaggrd , Klinta and Tulle sbo in Skgne . The subzonal association consists besides the index- species of 0. confZuens am�i quus. OuZ. eZegans. "S. " aff . snajdri. Ozarkodina sp . Stratigraphically the subzone occupies nearly all of the Kuressaare Formation (except ots uppermost part) . Ozarkodina s. eosteinhornensis s . str . Subzone . The lower boundary is determined by the appearance of specimens of the typical subspecies in the topmost part of the Kuressaare Formation . "S . " aff. snajdri terminate within this subzone . The subzone corresponds to the Aigu Beds of the Kaugatuma Formation . Ozarkodina s. eosteinhornensis canadensis Subzone . This subzone determined by canadensis morphotype , covers the Lõo Beds of the Kaugatuma Formation . The lower and upper boundaries are indistinct as the appearance of canadensis and remscheidensis morphotypes is gradual. Besides the index morphotype there can also be found the rem scheidensis morphotype but in small numbers . Ozarkodina s. eosteinhornensis remscheidensis Subzone . The subzone is distinguished by the predominance of the remscheidensis morphotype at which the canadensis morphotype continues their existence . A characteristic feature of this subzone is that 0. confZuens is represented by subspecies with a spathognathodontan element "S . " primus nasutus appearing in the upper part of the canadensis Subzone . Basin zones Po Zygnathoides siZuricus Zane This zane is def ined on the occurrences of the index-species in two sections : Pavilosta (Latvia) , depth 756 .0 m (2 specimens) and Vidukle (Lithuania), depth 1166.2 m (1 specimen ). Besides the index- species "P. " emarginatus (Pavilosta , depth 750 .3 m) and D. dubius. P. dubius (Vidukle , depth 1166.2 m) have been identified . The last two give reasan for correlation the siZuricus Zane with the D. dubius Subzone of the shelf area , at least with a part of it . Ozarkodina s. eosteinhornensis Zane The zane wa s described above in mare detail . In general the conodont complex is analogous with that of the shelf area . However , offshore deposits finds of all conodonts , also of the index- species , are comparatively rare . Thus reliability of draw inf zonal boundaries depends , first of all , on the frequency and sizes of samples . 86 Re ferences Chlupa , J. , K i , J. , Schönlaub , H. P. , with contr . Kla per , G. , Zikmundova , J. Silur � r � i? ian and Devonian conodont localities of the Barrandian . Second European conodont s�nposium - ECOS II . Guidebook , abstracts . Abh . Geol . Bundesanst. , 1980 , vol . 3 5, p. 147-180 . Helfrich, e. T. Silurian conodonts from Wil l s Mountain anticline , Virginia, West Vir ginia and Maryland . - Geol .. Soc . America Spec . Paper , 1975, vol . 161, 82 p. Jeppsson , L. Notes on some Upper Silurian multielement conodonts . - Geol . F8ren . Stock holm Förhandl. , 1969, vol . 91, p. 12-24 . Jeppsson , L. Some Silurian conodont apparatuses and possible conodont dimorphism. - Geologica et Palaeontologica, 1972, vol . 6, p. 51- 69 . Jeppsson , L. Aspects of Late Silurian conodonts . Fossils and Strata , 1974 , vol . 6, p. 1-54 . Klapper , G. , Murphy , M. A. Silurian - Lower Devonian conodont sequence in the Roberts Mountains Formation of Central Nevada . Univ . Calif . Publ . Geol . Sci., 1974, VO 1 111 1 6 2 p • Wa lliser , 0. M. Conodonten des Silurs . Abh . hess . L.-Amt . Bodenforschung , 1964, Bd . 41, 106 S. BHRpa B. �. COCTaB H pacnpOCTpaHeHHe KOHO�OHTOB B CHnype DpHOanTHKH / CKB . Oxecaape , KYHKOHR , YKMepre H �p . / . B KH.1 �a�HH H �ayHa CHnypa DpHOanTHKH . TannHH , 1977, e. 179-192. BHRpa B . CnaTOrHaTO�YC� /KOHO�OHT�/ BepXHero CHnypa 3CTOHHH . B K H .: DaneOHTOnOrHH �peB Hero naneosoH DpHOanTHKH H no�onHH . TannHH , 1982 a , e. BHttpa B. MenKOBO�H�R KOHO�OHT C tenognathodus murahisoni fi03�Hero BeHnOKa 3CTOHHH . B KH .: CooO�eCTBa H 0H030H� B CHnype DpH OanTHKH . TannHH , 1982 01 C. n. K. , raRnH Te YnbcT P. �. 3oaanbH�e no�as�eneHHH Bepxaero CHnypa B naTBHH . B KH . : PerHoHanbHaH reonorHH DpHOanTHKH . 3HHaTHe , PHra , 197 4 , e. ?8-44 . HeCTOp X. 3. , 3RHaCTO P. 3. �a�HanbHO-Ce�MeHTOnOrH�eCKaR MO�enb CHnypHRCKOrO DaneoOan- THRCKOrO nepHKOHTHHeHTanbHOrO OacceR Ha . B K H . : �a�HH H �ayHa CHnypa DpH OanTHKH . TannH H, 1 9 7 7 , e. S9-121 . 87 ВЕРХНЕСИЛУРИЙСКИЕ МЕЛКОВОДБЫЕ И ГЛУБОКОВОДНЫЕ КОНОДОНТЫ ПРИБАЛТИКИ В. Вийра Верхt:есилурийскиЕ: конодонты Северной Прибал1:ики анализированы на основе богатой коллекции, nроисходящей из разрезов 7 буровых скважин и 5олее чем 30 обнажениИ /рис. 1, 2, 3/. Рассмотрено расnределение конодонтоБ в зазиенмости от фациальной з::>нал.но..:ти Палеебалтийского бассейна. Сообщество Ctenognathodus расnространено в лагунной и от мельнсй, сооб�ества Ozarkodina и OuZodus в отмельной и открытоruельфовой зонах. Канодон ты склонавой зоны nредставлены сообществом KockeZeZZa и PoZygnathoides. На основании фациального расnределения конодонтов nриведено две зональные схемы: для шельфа и для бассейновей часть /табл./. Первая содержит зоны С. �Archi�oni, Ozarko dina sp. S - О. co"fZuens cornidentatus, D. dubius - "Belodus" sp. и О. о. eostein hor•nensis /с четырьмя nодзонами/. Схема бассейновой части содержит зоны sagitta, silu ricuв и eosteinhornensis. 88