GEOLOGICA BALCANTCA, 21. 4, SofiJ, August . 1991 , p. 55-72

Conodont biostratigraphy of the Lower Devonian from Southwest Bulgaria

I/iana Bonceva

Geological In st itute, Bulgarian Academy of Sciences, 1113 Sofia (Receil•ed 06. 06. 1990; accepted ill revised form 18. 09. 1990)

If. Eou•1e11a- f(ouodolilmw.l H JOHhl He HB:'TifiOTCll 8)J.eKBaTHO COTIOCT

E ==J r J____..&J~

0 ' Tr tin

e?··

~ , ~ s~ . n --·-----·~-- '-=>~· ::=~doo~-=1~-----_j

Fig. 1. Location scheme of I 0 sections in the study area from Southwest Bulgaria. I - Vra-b~a Formation (Lower- Middle Devonian), 2- section studied with their number: 2 Diil-boki dol, 3 Bela voda, 4 western slope of the Dalboki dol, 5 Kolina mahala, 6 Zemen, 7 Del, 8 Gorna Vrab~a. 9 Vukasinova mahala I, 10 Vukasinova mahala II, I Murcno

near the village of Mureno (Dubice mahala) and tbe Vukasinova mahala district- 1st and 2nd section (see Fig. 1). The latter three sections are published and will not be described here but due to the generalizing character of the present paper, the paleontologic data of these sections will be used for the division of the conodont zones. The section near the village of Mureno (Dubice mahala) was described and figured by Bon c eva (1987), while the sections near the Vukasinova mabala were published by Zag or c e v, Bon-

•ceva (1988).

Description of ·the sections

A section along Dalboki Dol (Fig. I, Fig. 2)

The section lies north of the village of Mureno and west of the Voinci mahala. Due to the very complicated tectonics there are two trends of thrusting in the section. In this case of scaling the role of substratum is played by the Upper Devonian sediments, over which Emsian and Lower Eifelian sediments are thrusted in the reverse order. The second tectonic scale is built up of Upper Emsian sediments.

V·rabca Formation (thickness 548 m), (Emsian- Lower Eifelian), (packets No 4-1)

4i. (9 m)

Nodular limestones up to thin-layered, interbedded by grey-greenish argillites. Remnants of Tentaculites and Crinoidea can be observed on the surface of the limestones. In sample 204- 8 m above the base of the packet the following conodont species were found: Ozarkodina media Wall i s e r, 1957, Polygnathus coo-

. peri cooperi K I a p per, 1971. Only the following species is present in sample 1136, 6 m above the base: Spat-ltog?Zathodus carinthiacus S c h u I z e, 1968. The association found in sample 355,3 m above the base of the packet, is: Belodella devonica (Stauffer, 1940), B. triangularis (Stauffer, 1940), Hindeodella pri-scilla Stauffer, 1938, Plectospathodus a/ternatus W a IIi s c r, 1964, Polygnathus linguiformis bultyncki Wed dig e, 1977, P. serotinus T e If or d, 1975. The following species were found in sample 880, 2 m above the base of the packet: Ozarkodina typica denckmanni Z i e g I e r, 1956, Pandorinellina steinhornensis steinhornensis (Z i e g I e r, 1956), Polygnathus cooperi cooperi K I a p per, 1971. The following species were

56

found from the ba se upwa rds wi thin a met re in sample 877: Befodel/a dtmmica (Stauffe r , 1940), B. trian-gularis (S t a u f f e r, 1940), Hindevdel/a priscil/a S t a u f f c r, J 938, Oneothodus beckmanni B i s c hoff & San n e m a nn, 1958, Ozarkodina t1•pica denckmanni Z i e g I e r, 1956, Pfectospathodus afternatus W a I-I i s e r, 1964, Tricfwnodel/a excarota (ll r a ns o n & Me hI , 1933). ---- - - --- -· .rapid lithologic transition ---- ----------

4 h. (13 m)

Black , strongly folded lyditcs. Ther-! a re tw0 conglom~ rate inte rbeds, 0,6 m and 0,7 m thick, in the base of the packet. They contain fragments of lydites and limestones with a limy-sandy cement. Between the two conglomerate interbeds there a re also sandy limestones 0,5 m thick where tiny lydite fragments are found.

tectonic boundarY -- - - --- --- -

4g. (1.5 m)

Limy-sandy, rusty-yellowish argillites. - - - - ------- - ------tectonic boundary-------- ------ - - ----

4f. (3 m) Grey limestones containing a lot of calcite veins. The thickness of the separate layers is 80-90 em. The fol-lowing conodont species were found in sample J 106- 3 m above the base of the packet : Hindeodel!a pris-ciffa, S t a u f f e r, J 938, Neoprionidus biscurvatus (Bra n so n & Me h I, J 933), Ozarkodina typica denck-manni Z i e g I e r, 1956, Pfectospathodus a/ternatus W a IIi s e r, 1965 , Polygnathus cooperi cooperi K I a p-p e r, 1971, P. cracens K I a p per, Z i e g I e r & M a sh k ova, 1978, P. lingu(f"ormis buftyncki Wed d i-g e, J 977, P. serotinus ,T e I f o r d, 1975. Only one species was found in sample J I 05 - 2 m from the base: Icriodus bi/atericrescens Z i e g I e r, 1956. The following conodont species are comprised in samples I 102 -1 m above the base of the packet: Belodefla triangularis (St a uffer, 1940), Hindeodelfa equidentata (Phi-1 i p, I 966), H . prisciffa, S t a u f f e r, 1938, Oneothodus beckmanni B i s c h o f f & S a n n em an n, 1958, Polygnathus cracens K I a p per, Z i e g 1 e r & Mash k ova, 1978, P. im·ersus K I a p per & John-son, 1975, P. linguiformis buftyncki Weddige, 1977, P. serotinus Telford, 1975, Spathognathodus! carinthiacus, Shu 1 z e, 1968.

--- -----tectonic boundary _______ _

4e . (4 m)

The packet is built up of 4' lydites, which arc strongly folded and form characteristic flash folds. The thickness of the separate layers does not exceed 6- 8 em.

tectonic boundar:v- - · ----------------

4d. (8 m) Alternation of plate, argillaceous limestones with argillites. The following species were found 8 m above the base of the packet in sample 1004: Hindeodelfa equidentata (Phi 1 i p, 1966), Neoprionidus bicurvatus (Bra n-s o n & Me h 1, 1933), Oneothodus beckmanni B i s c h o f f & Sa n n e m a n n, I 958, Ozarkodina media-W a I I i s e r, I 957, Panderodus tmicostatus (B r a n so n & M e h I, I 933), Tric/zonode/1 a excavata (B r a n-s on & Me h 1, 1933). The species found 7 m above the base in sample 1003 are: Hindeodel/aprisciffa S tau f-fe r, 1938, Oneotlwdus beckmanni Bis c hoff & San n em ann, 1958, Ozarkodina media W a 11 is e r, 1957, Ozarkodina typica denckmanni Z i e g 1 e r, 1956, is found in sample 87-5 m above the packet base. Three species are found in sample I 087- 4 m above the base: Belodella devonica (S tau f f e r, \940), H in-deodella equidentata (Phi 1 i p, 1966), H. prisciffa Stauffer, 1938. At a distance of 3,5 m above the pa-cket base in sample 78 were found the following conodont species : Hindeodella prinscif!a S t a u f f e r, I 938, Ozarkodina media W a 11 is e r, 1957, Panderodus unicostatus (Branson & Me hI, 1933), Plectospatho-dus alternatus W a I I i s e r, 1964, Polygnathus serotinus T e If or d, ·1975, P. sp. n. A. Only one species was found 2 m above the packet base in sample 1084b: Icriodus hudd/ei ssp. ind. Characteristic taxa were found in the packet base, in sample 1084•- Polygnathus cooperi cooperi K 1 a p per, 1971, P. inver.ms K I a p-per&Johnson, 1975, P. serotinus Telford, 1975. --- - - - ----------gradual lithologic transition -

4 c. (4 m)

Plate, light-grey, fine-grained limestones. The following conodont association was found at a distance of 4 met-res above the base of the packet in sample I I 16: Be/ode/fa triangularis (Stauff e r, 1940), Hindeode!fa equi-dentata (Ph i I i p, 1966), H. priscilla S t a u f f e r, 1938, Icriodus huddlei ce/tibericus C a r I s & G and I, 1969, /. ltudd/ei curvicauda CarIs & G and I, 1969, Neoprioniodus bicurvatus (Branson & Me h 1, 1933), Ozarkodina typica denckmanni Z i e g I e r, I 956, while in the very base of the packet in sample 66 there is only one taxon : Spathognathodus carinthiacus S c h u I z e, 1968. - ·--- · ··- - - · -···--·- - - - ·- - - - ------ -tectonic boundary . - ·---· ·--- -- -· - - - - ----· - -- -- --

57

4b. (2 m) Black, strongly bent lydites.

. ·- ------ - tectonic boundary _______ _

4a. (5 m).

Plate, light-grey, fine-grained limestones. The following conodont association is established 4 m above the packet base in sample 1103: Hindeodella equidenrara (Ph i I i p, 1966), H. priscilla S t a u f f e r, 1938, Neo-prioniodus hicurl'a/!IS (B r::: n so n & Jl.-1 e h I, 1933), Oneorhodus heckmanni B i s c h o f f & S a n n c m a n n, 1958, Ozarkodina typica denckmanni Z i e g I c r, 1956, Panderodus unicostatus (B r a n so n & M e h I, 1933 ), Pandorine/linll steinlwmensis srein/;omensis (Z i e g I e r, 1956), P!ec/osparhodus a/remarus W a IIi s e r, 1964, P. extensus Rhodes, 1953. At a distance of a metre one association is found in sample 161 : Belodella deronica (S t a u f f e r, 1940). B. lriangu/(IJ is (S tau f f e r, 1940), Hindeodella equidenrata (Phi I i p, 1966). H . prisr:illa S t a u f f e r, 1938, Neoprioniodus bicun,atus (B r a n so n & M e h I, 1933), N. mu!riformis W a I-I i s e r, 1964, Oneothodus beckmanni B i s c h off & S a nne m a n n, 1958. Pol)gnutllus cracens K I :.1 p-p e r, Z i e g I e r & M a s h k ova, 1978, P. linguiformis bulryncki W c d dig e, 1977, P. serotinus T e I-f o r d, 1975, Tricllonodel/a excarara (B r a n so n & Me hI, 1933). ---------- tectonic boundary --·- ··

3. (5 m) Second-order thrust (tectonically re-worked phyllitized slates)

------ - ---- line of tectonic thrusting ------------- -- ----

2. (14.5 m)

Greyish-green nodular limestones and greyish-green slates forming an alternation. The following conodont association was found 13 m above the packet base in sample 155: Belodella deronica (S t a u f f e r, 1940), J!indeodella equidentaw (P h i I i p, 1966), Icriodus fusiformis C a r I s & G a n d 1, 1969, /. huddlei cun•icau~ da CarIs & G a nd I, 1969, Neoprioniodus himrvatus (Branson & Me hI, 1933), Ozarkodina /ypica denckmanni Z i e g I e r, 1956, Polygnathus g"ronbergi K I a p per &'Johnson, 1975. The association which is 2 m above the base in sample 156 consists of the following taxa : Belodella de i'Onica (Stauff e r, 1940), Jcriodus jilSijormis C a r I s & G a n d I, 1969, Oneothodus heckmanui B i s c h o f f & S a nne m a n n, J 958, Panderodus unicostallls (Branson & Me hI, 1933), Polygnathus tnonbergi K I a p per & J o hn son, 1975, Triclwnodella excavata (B r a n so n & M c h I, 1933). ··- ·- · - - --- tectonic boundary--~-·--·---- -- ------ -----

l. (13 m)

The packet comprises light -grey plate limestones and greyish-yellow slates forming an alternation. The con

4b. (3 m) The packet consi sts cf black slates and black lydites. _ ___ ____ tectonic boundarY------------------ --

4 c. (7 m)

Plate up to thick-leyered grey, fin c-gr;;ined limestones. The species presenting in samples 1018- 7 m up-wards from the packet hasc, are : Belodella triangularis (Stauffer, 1940), Oneothodus beckmanni B i se-ll o f f & S a n n e m a n n 1958, Plectospathodus e.rtensus R h o cl e s, I 95 3, Polygnathus imersus K I a p-per&Johnson, 1975, P. serotinus Telford. 1975. The conodont as~oc i a tion in sn mple 1017 - 6 m above the packet base comprises: Hindeodella equidemata (Phi I i p, 1966), O::arkodina typira denckmanni Ziegler, 1956, Polygnmhus im•e.sus Klapptr&Johnson, 1975, P. serotinus Telford, 1975. The following species were found 5 m above the packet base in sample 1016: Icriodus huddlei celtiherirus C a r I s & G a n d I, 1969, I . huddlei cu. 1·icauda C a r I s & G.a n d I, 1969, Ozarkodina t vpica denckmanni Z i e g I e r, 1956. Four m above the base in sample 1015 are fcund: J-findeodeila equidentata (phi I i p. 1966), Neoprioniodus bicurvatus (Branson & Me hI. 1933). Ozarkodina typica denckmanni Z i e g I e r, !956. The conodont association in sample I 07 - 3 m above the packet base, comp ri ses: Neoprioniodus bicurratus (Branson & M c hI , 1933), Oneorhodus beckmanni Bi sc hoff & San 11 em ann, 1958, Ozarkodina typica denckmanni Z i e g I e r, 1956, 0::. media W a I I i s e r, 1957, Plecto spathodus extensus Rhode s, 1953, Polygnathus cooperi cooperi K I a p per, 1971, P. coopri secus K I a p per, Z i e g I e r & Mash-k ov a, 1978, Polyf!nathus cracens K I a p per, Z i e g 1 e r & Ma s h k ova, 1978, P. inver sus K I. a p-p e r & J o h n so n, 1975, P. lin{!tujormis bultyncki We d d i g e, 1977, P. serotinus T e I f o r d, 1975, P. quadratus K I a p p e r, Z i e g I e r & M a s h k o v a. 1978. The species found in sample 112 - 2 m abo-ve the packet base a re: Belodella devonica (St a uffer, 1940), 8 . triangularis (St a uffer, 1940), Hin-deodello cquidemota ( P h i I i p, !966), Plecto~>patlwdus ex ten sus R h o d e s. J 953. The specie s found in the base of the packet in sample 83 a re: I-findeodella priscilla Stauffer, 1938, Pandorinel/ina steinlzoruensis -steinhomensis (Z i e g 1 e r, 1956), Polygnathus inver sus K I a p p c r & John son, 1975.

----------tectonic boundary • --- --·----· .. - - --

4 j. (16.5 m)

The packet is built up of plate, grey, fine-grained limestones; light-green phyllitized slates, black lydites and two inte rbeds of breccia conglomerates (fragments of limestones and lydites with calcareous cement). The following species were found 15 m above the paket base in sample 142 /3: Belodella devonica (S t auffer, 1940), B. triangularis (S t a u f f e r, 1940), Hindeodella equidentata (P h i I i p, 1966). H. priscilla S t a u f-fe r, 1938, Neoprion iodus bicurvatus (Branson & Me hI. 1933), icriodus :!ff. alternatus Bran so n& Me hI, 1934, / . corniger ancestrali., Wed d i g e, 1977, I. latericrescens B r a n ~ o 11 & M e h 1, 1938. 1. la-tus A I-R a w i, 1977, Oneotltodus beckmanni B i s c hoff & San n em a nn, 1958, Polygnathus cooperi cooperi Klapper, 1971, P. cooperi secus Kl a pper, Ziegler&M as hk ova, 1978, P. inversus K I a p p e r & J o h n so n, 1975, P. serarinus T e I f o r d, 1975, Pandorinellina steinlwrnensis buchanensis (Phi I i p, 1966). Samples 106 and 108 - II m from the base upwards, conta in: Hindeodella equidentata (Phi-1 i p, 1966), Panderodus wticnstatu s (Branson & M chI, 1933), Polyg'nathus cooperi cooperi K I a p per, 1971, P. seratinus T e If o rd. 1975. A second brecc ia-conglomerate interbedding lies 10 m above the base of the packet. Limestone fragments we re repeatedly tested but no conodont faun a was established. Immedia-tely under the brecci:>. -conglomerate, 9 m above the packet base in sa mple n 1., the following conodont sp('-cies were found: Plectospathodus alf1!rnafll .' W a I I i s c r, 1964, P. £'Xtensus R h o de s, .195 3, Polygnathus cooperi cooperi K I a p per, 1971, P. mstaf11.1· palltlus K I a p per, 1971 , Polygnathus serotinus T c I r or d. 1975. Above 100 specimens were found in sample 2a, 8 m above the packet b:~se; out of them 50 being Polygnathus serotinus T e If or d. 1975, and the other tax:t of the associa tion are: Hindeodella equidentatn (Phi I i p, 1966). Neoprioniodus bicurvarus (Branson & Me h J, 1933). N. multiformis W a IIi s e r, 1964, Oneotlwdus beckmanni B i s c hoff & S a nne il1 a n n, 1958, Ozarkodina ty(lica denckmanni Z i e g-1 C r, 1956, Oz. media, W a I I i s e r, 1957, Panderodus unicostarus (B r a n so n & Me h 1, 1933), Pelekysg-nathus serrarus elongatus CarIs & G and I, .1969, Plectospathodus ex tensus Rhodes, 1953, Polygnathus coopericooperi Kl a pp e r, l971,P.cooperi ~>ecus Klapper, Ziegler&M as hko va, 1978,P.in-versus K I a p p c r & John s on, 1975, P . linguiformis bultyncki Wed dig e, 1977. The following species are compri sed in sample 57- 7 m above the packet b:~se: Belodella triangularis (S tau r f c r, 1940), Hin--deodella priscilla S t a u f f c r. 1938, Icriodus neradensis J o h n so n & K I a p p e r, 1981, I. rectus We d-d i g e & R e q u a r d, 1985, Poh 'f!llathu .~ caoperi coo peri K 1 a p p e r, 197!. P. costarus partitus K I a p-p e r, Z i e g I e r & Mash k o v u, 1978, P. costa/us parulus K I a p per, 1971 , P. pseudoserotinus Maw-son, 1987, P. sp. n. A, P. im•ersus Klapper&Johnson, 1975 , P. serotinus Telford, 1975. Sam-ple 18 a, lying 6 m above the packet base, compri ses: Hindeodella priscilla Stau ffer, 1938, Neoprioniodus bicurvatus (B r a n so n & M e h I. 1933), O::arkodina media W a I I i s e r, 1957, Oz. typica denckmanni Z i e g-1 e r, 1956, Plectospathodus alternatus W a I I i s e r, 1964, Pol. im•ersus K I a p p e r & J o h n so n, 1975, P. ling111jormis bultPncki Wed dig e, 1977, P. serotinus T e If o r d, 1975, P. sp. n. A, P. pseudoseroti-nus Mawson, 1987. Then come 5 m where lydites outcrop. They are 2m thick. Then come plate lime-stones and 1 breccia-conglomerate interbed. They were stud ied in details but fauna was not esta blished. -----------·- -- line of tectonic thrusting _ ____ _

59

Black argillaceous limestones, black Jydites and black argillites differentiated in separate packets, outcrop in the contact of the Vrab~a Formation and as a basement in this section. On the very contact with the Vrab-ca Formation sediments there are black limestones from which 4 samples were treated (at a distance of 10 em). In these samples (samples 86a, b, c, d) a lot of specimens belonging to the Upper Devonian, genus Palmatolepis were established. The predominant species is Palmatolepis triangularis, San n em ann, 1955.

Section along the Bela Voda l'af!ey (Fig. 1; Fig. 2)

The section lies to the north of the village of Mureno and can be traced in the Bela Voda valley, which lies west of the Dalboki Dol valley. The total thickness of the outcrop is 1700 m. In 830 m of these the sediments of the Vrabca Formation can be traced. The section has a NNW-SSE orientation. In the NNW the basement of the Vrab-ca Formation is not outcropped, while in the SSE the sediments of the Tranovdol For-mation are the cover. The contact is tectonic.

Tranovdol Formation (thickness- 840 m), (Lower Givetian- Lower Frasnian, according to Spassov (1973)).

The formation is presented by an alternation of pebble conglomerate, sandstones and argtllites. ------- tectonic boundary---·-----

Vrabca Formation (thickness- 830 rn), (Lower Emsian), (packet No. 5-l)

5. (6 m) rregular alternation of black argillites and black lydites.

·---- --tectonic boundarY - · ·------·-.. -... - .. ------- ----

4. (54 m) Thin-bedded, ligh-grcy, micro-grained limestones interbedded by light green argillites. Sample 13 - 53 m above the packet base, contains the following conodont fauna: Ozarkodina media W a IIi s e r, I 957, Oz. ty-pica denckmamzi Z i e g I e r, 1956, Pandorinellina steinhornensis steinhornensis (Z i e g I e r, 1956), Polyg-nathus perbonus (Phi 1 i p, 1966), Spathognathus inc/inatus inclinatus (Rhodes, 1953), S. inclinatus wur-mi B i s c h o f f & S a n n e m a n n, 1958. -------- gradual lithologic transition--------

3. (295 m) Light-green slates with rare and poor in thickness interbeds of nodular, greyish yellow, argillaceous limesto-nes. No fauna was established.

.tectonic boundary ---------

2. (10 m) Black graptolithic argillites. The following graptoliths were established: Colonograptus co/onus (B a r ran-d e, 1950), Plectograptus macilentus (T 6 r n qui s t, 1887).

----- --- tectonic boundary---------------------..

1. (465 m) Light-green slates with rare, poor interbeds of nodular, greyishyellow, argillaceous limestones. No fauna was established from the 93rd m up to the 465 m in the packet. There are no outcrops in the following 78 m. Seven m above the packet base in sample I, a more substan-tial in thickness nodule contains the following conodont fauna: Hindeodella priscilla Stauffer, I 938, Ozar-kodina typica denckmanni Z i e g l e r, 1956, Spathognathodus inc/inatus wurmi B i s c h off & Sa n n em a n n, 1958. The basement is not outcropped.

Section along the ll'estern slope of Dalboki Dol (Fig. I ; Fig. 2).

The section is situated in the northern end of Dalboki Dol along its western slope up to the ridge separating the vallE-ys of Bela Voda and Dfllboki Dol. The basement and the cover of the sediments of the Vrabca Fotmation in this section are not outcropping.

60

Vrabca Formation lthickness -- 97 m), (Lower Emsian), (packet No. 6-1)

6. (2 m)

I.ight-grey limestones with sparce arg1llites interbeds. The limestones are thick-layered, the thickness of the separate layers being from 50 to 80 em. The following conodonts were established in sample 81-2 m from the packet base: Neoprionidus bicurvatus (Branson & Me hI, 1933), N. excavatus (Branson & Me hI, 1933). --- - ------- ----rapid lithologic transition - - - ------------

5. (4 m)

Conglomerate of lydite and calcareous fragments with a sandy calcareous cement. The individual fragments have a diameter of 5 to 10 em. Conodonts were found in the calcareous fragments. The following conodonts belong to sample 76: Polygnathus gronbergi K I a p per & John so n, 1975, P. perbonus (Phi I i p, 1966), Ozarkodina typica denckmanni Z i e g I e r, 1956. Sample 77 contains: Ozarkodina typica denckmanni Z i e g-1 e r, 1956, Polygnathus gronbergi K I a p p e r & J o h n so n, 1975, Spathognathodus cf. inclinatus (R h o-des, 1953), Trichonodella excavata (Branson & Me hI, 1933}.

-- --- rapid lithologic transition----------------

4. ( l m)

Thin-layered, purple-red, sandy limestones. The individual layers are 1-2 em thick. - - -- · rapid lithologic transition----------------

3. (15 m)

Alternation of light-grey, micro-grained, plate limestones with light-green argillites. The following species were established in sample 74- 15 m above the packet base: Belodella triangularis (S t a u f f e r, 1940), Hindea-della priscilla Stauffer, 1938, Icriodus nevadensis J c h n son & K I a p per, 1981.

. tectonic boundarY------------ ----- -

2. (10 m)

Black, strongly folded lydites. --------- tectonic boundary

l. (65 m) Alternation of lens-like to thin-layered limestones with light-green argillites. The thickness of the individual layers varies from 7-8 mm up to I em. There are mainly argillites in the packet. Sample 72- 65 m abo-ve the packet base contains: Panderodus unicostatus (Branson & Me hI, 1933), Pelekysgnathus serratus elongatus CarIs & G and I, 1969. The following conodont species were found in sample 68- 30 m above the packet base: Hindeodella equidentata (Phi I i p, 1966), Icriodus sp. ind., Pandorinellina steinhomensis steinhornensis (Z i e g I e r, 1956), Polygnathus sp. ind. , Spathognathodus sp. ind. The species presented in sam-ple 63- 5 m above the packet base, are: Icriodus steinachensis A I- Raw i, 1977, P/ectospatlwdus a/ternatus W a IIi s c r, 1964, P. extensus Rhodes, 1953.

Section near Kolina Mahala (Fig. I; Fig. 2).

The se-ction lie-s 3 km north of the village of Mureno and 250 m e.ast of Kolina Mahala. Its oritntation is NW-SE. In the NW the Devonian sediments are covered by flysch se-diments belonging to Late Jurassic (Tithonian-Berriasian flysch). The boundary IS tectonic.

Vrabca Formation (thickness- 42 m), (Emsian), (packet No 3-1)

3. (17 m)

Plate, thick-layered limestones with individual interbeds of phillitized argillites. The following conodont asso-ciation was found in sample 382- 16 m above the packet base: Belodella devonica (Stauffer, 1940), B. triangularis (S tau f f e r, 1940), Hindeodella priscilla S t a u f f e r, 1938, Icriodus hudd/ei celtibericus CarIs & G and I, 1969, Neoprioniodus bicurratus (Branson & Me hI, 1933), Ozarkodina typica denck-manni Z i e g I e r, 1956, Plectospathodu> extensus R h o de s, 1953, Polygnathus cracens K I a p p e r, Z i e g-1 e r & M a s h k ova, 1978, P. inver sus K I a p p e r & J o h n son, 1975, P. quadratus K I a p per, Z i e g-

61

I c r & Mas 11 k 0 v a, 1978, Spathognathodus carinthiacus Schulz c, 1968, Trichonodella cxcavata (Bran-son&Mchl, 1933). - --------- ------- --tcctc-nic boundarY---- - - - -

2. (5 m) Black, strongly folded lyditcs.

- - --- -- --- tectonic boundarY-------- - -- -- --- - ---

l. (20 m)

Greyish-green argillites with rare reddish lenses of limestones. The following species were found in sample 99p - 20 m a bove the packet bast:: Belodella resinw (Ph i I i p, 1965), R. triangularis (S t a u f f e r, 1940), Hin-deodella priscilla Stauffer, 1938, Jc:riodus beckmanni-sinuatus K I a p p c r, Z i e g I c r & M ash k ova, 1978, Neoprioniodus excavatus (B r a n so n & M c h I, 1933), Panderodus unicostatu.1· (B r a n so n & M e 11 I, 1933), Plectospatlwdus altema/its W a I I i s c r, 1964, Polygnathus inrersus K I a p per & J o h n so n, J 975, Polygnathus laticostatus, K I a -p p e r & J o h n son, 1975, Spathognathodus inclinatus wurmi B i s c hoff & S a n n em ann, 1958. Then follow 10 m without outcrops. -The following taxa were found in sample 995 - 4 m above the packl! l base: Oneothodus beckmw111i Bis choff & Sa nne mann, 1958, Ozw·kodina media W a I I i s c r, 1957, 0::. typi

113 - I m above th~ packet base arc: H indeodella equidentata (P 11 iIi p, 19()6), laiodus wos.c:fwlidti Z i e g-1 e r, J 960, Neop rivuiodus biscurvatus (B ran son & Me hI, 1933), Oneothodus beckinanni B i s c hoff & S an n e m a n n, !958, Pandorinellina nwsarn (S c h i:i n I a u b, 1980), P. steinhomensis remscheidensis (Z i e g-1 c r, 1960). In the base of the packet in a limestone layer 10 em thick, in sample Z 8, the species found arc : O::arkodina media W a II i s e r, 1957, Pandorinellina masara (S c h i:i n I a u b, 1980), P. steinhomensis evsteinlwmcnsis (W a IIi s c r, I 964), Pelekysgnathus serratus elongatus C a r I s & G a n d I, I 969.

gradual lithologic tra nsition ___ ·-·-- -·- ------···------

J. (8S m)

Alternation of th in-l

The following 75 m have no outcrops. The species contained 38 m above the packet base in sample 29 are: Neoprioniodus bicurvatus (Branson & Me hI, 1933), N. excal'a/us (Branson & Me hI, 1933), Ozarkodina typica denckmanni Z i e g I e r, 1956, Triclwnodella exca1•ata (Branson & Me hI, 1933). No outcrops were found in the following 19 m. No conodont fauna was established 19 m above the base in sample 28 and in sample 27- II m above the base.

------- - lithologic transition --- ----

2. (60 m) Nodular limestone amid greyish-green argillites. The following conodont species are present in sample 26-58 m above the base of the packet: Belodella resima (Phi I i p, 1965), B. triangularis (Stauffer, 1940), Hindeodel/a equidentata (Ph i I i p, 1966), Icriodus huddlei curvicauda C a r I s & G a n d I, 1969, Neoprio-niodus bicurvatus (Branson & Me hI , 1933), Plectospathodus extensus Rhodes, 1953. The species established 12 m above the packet base in sample 24 are: Belodella dei'Onica (Stauffe r, 1940), B. trian-gularis (Stauffer, 1949), Icriodus angustoides castilianu .. CarIs, 1969, f . huddlei curvicauda CarIs & G and I, 1969, Ozarkodina typica denckmanni Z i e g I e r, 1956. -------- - lithologic transition - -- ---- - -- . --·- ·-- - - ------· ·- ---

Solid, thick-layered limestones. There is only one taxon 30 m above rile base in sample 14: Icriodus post-woschmidti Mash k ova, 1968. The following species were established 21 m above the base in sample 13 : Belodella devonica (St a uffer, 1940), Icriodus woschmidti Z i e g I e r, 1960, Ozarkodina media W a II i-s e r, 1957, Oz. typica denckmanni Z i e g I e r, 1956, Panderodus unicostatus (Branson & Me hI, 1933), Plectospathodus alternatus W a IIi s e r, 1964, P. extensus Rhodes, 1953. The species present in sample 12 - 10 m above the base are: Ozarkodina media W a IIi s e r, 1957, Plectospathodus altematus W a IIi s e r, 1964, P. extensus Rhodes, 1953, Spclthognarhodus inclinarus wurmi Bischoff & San n em ann, 1958, Trichonodella excavata (Brans o 1 & Me hI, 1933). The conodont associdtion in sample II - 5 m above the base comprises the following species : Belodella triangularis (Stauffer, 1940), Hindeodella pri11::illa S t a u f f e r, 1938, Icriodus woschmidti Z i e g I e r, 1960, Neoprioniodus bicurvarus (B r a n so n & M e h I, 1933), Neoprioniodus excavatus (Branson & Me hI, 1933), Ozarkodina media W a IIi s e r, 1957, Pan-dorinellina masara (Schon I au b, 1980), P. steinlwrnensis remscheidensis (Z i e g I c r, 1960), Plectospa-tlwdus exrensu.1 Rhodes, 1953.

--- -----· line of tectonic thrusting - ------- - - --- --- - - - --

Upper Jurassic flysch sediments are outcropping in this section at the contact with the Vrabca Focmation and at the same time being a basement of the formation.

Section near the ~·illage of Go rna Vrabca (Fig. I ; Fig. 2)

The section lies south of the village of Gorna Vrabca along the road before the fork to Vuka sinova Mahala. The substrate of the &;diments of the V .abca Formation is built up of black argillites with Ludlow graptolitic fauna. The Vrabca Formation cover in this section consists of Pliocene sediments. The overall thickness of the sediments in the sec· tion is about 26 m, in 18,8 m of them Lower Devonian sediments are outcropping.

Vrabca Formation (thickness -18.8 m), (Uppt:.r Lochkovian- Lower Emsian), (packets No. 3-1)

3. (6.2 m) Nodular limestones up to thin-layered, greyish-green argillites and siltstones. The argillites predominate. The following conodont association was found in sample 48 /11-6 m above the base: Belodella devonica (S t a l.i f. fer, 1940), B. resima (Phi I i p, 1965), B. triangularis (Stauffer, 1940), Hindeodella equidentata (Phi-1 i p, 1966), H. priscilla Stauffer, 1938, Icriodus bilatericrescens Z i e g I e r, 1956, I . claudiae K I a p-p e r, 1980, Icriodus corniger ancestral is Wed dig e, 1977, I. nevadensis Johnson & K I a p p e r, 1981, Neoprioniodus bicurvatus (Branson & Me hI, 1933), Ozarkodina typica denckmanni Z i c g I e r, 1956, Polygnathus dehiscens abysus Mawson, 1987, P. perbonus (Phi I i p, 1966). Above the packet base (5,7 m) in sample 990 /8 there are: Neopriniodus excavatus (Branson & Me hI, 1933), Icriodus huddlei celtibericus CarIs & G and I, 1969, Ozarkodina typica denckmanni Z i e g I e r, 1956, Spathognathodus inc/inatus wur-mi B i s c hoff & San n em ann, 1958. In sample 1 1-5 m above the base of the packet the following species were found: Hindeodella priscilla Stauffer, 1938, Neoprioniodus excavatu~ (Brans o n&M e hI, 1933), Panderodus unicostatus (Branson & M chI, 1933), Plecrospathodus alternatlts W a IIi s e r, 1964. The

64

taxa contained in sample 1 m, 4 m above the packet b~se are : Ozarkodina typica denckrrumni z i e g I e r, 1956, Pandorinellina steinlwrnensis steinhornensis (Z i e g I e r, 1956), Polygnathus dehiscens dehiscens Phi-1 i p & Jackson, 1967. The conodont association in sample 989 /6, 2.7 m above the packet base is: Belo-della triangularis (Stauffer, 1940), Hindeodella priscilla St a uffer, 1938, Oneothodus beckmanni B t-s c h o f f & Sa nne m a n n, 1958, Ozarkodina typic a deru kmanni Z i e g I e r, 1956, Pandorinellina masara (Schon I au b, 1980), P. steinhornensis steinhornensis (Z i e g I e r, 1956), P. steinhornensis telleri (S c h u 1-z e, 1968), Polygnathus dehiscens dehiscens Phi I i p & J a ckson, 1967. Samples 1H and 997 /7 contain the following conodont association, 2 m above the packet base: Belodella triangularis (Stauffer, 1940), Hindeodella priscilla Stauffer, 1938, Icriodus huddlei curvicauda Car I & G and I, 1969, Neoprioniodus excamtus (Branson & Me hI, 1933), Ozarkodina media W a IIi s e r, 1957, Panderodus unicostatus (B r a n s o n & M e h I, 1933), Pandorinellina masara (S c h o n I a u b, 1980), P. steinhornensis telleri (S c h u I z e, 1968), Pelekysgnathus serratus elongatus CarI s & G a nd I, 1969, Plectospathodus alternatus W a IIi s e r, 1964, P. extensus Rhodes, 1953, Pandorinellina optima (M o s k a I en k o, 1966). The following conodont species were found 1,5 m above the packet base (in sample 988 /4) : Belodella triangularis (S t a u f f e r , 1940), Hindeodella priscilla S tau f f e r, 1938, Icriodus bilatericrescens Z i e g I e r, 1956, I. fa/ax fa/ax CarIs, 1975, I. steinachensis A 1- Raw i, 1977, Neoprioniodus excavatus (Branson & M e h I. 1933), Oneothodus beckmanni B i s c h o f f & S a n n e m a n n, 1958, Ozarkodina typica denckmanni Z i e g I e r, 1956, Pandorinellina steinhomensis miae (B u I t y n c k, 1971 ), P. steinhomensis telleri (S c h u 1-z e, 1968), Polygnathus dehiscens abysus Mawson, 1987, P. dehiscens dehiscens Phi I i p & Jackson, 1967.

- tectonic boundary __ __ _

2. (7 m) The packet is built up of black lydites, which are strongly folded.

---- ------tectonic boundary _ _ ___ _ _ _

I. (5.6 m)

Nodular limestones amidst greyish-green argillites. There is only one species in sample 1u, 5,6 m above the packet base: Plectospathodus extensus Rhodes, 1953. The following association was found 5 m above the base in sample I: Belodella triangularis (Stauffer, 1940), Hindeodella priscilla Stauffer, 1938, Icriodus angustoides castilianus C a r I s, 1969, I. huddlei curvicauda C a r Is & G and I, 1969, Neoprionio-dus excavatus (Branson & Me hI, 1933), Pe7ekysgnathus serratus elongatus CarIs & G and I, 1969, Plectospatlwdus altemarus W a IIi s c r, 1964, P. extensus Rhodes, 1953. The conodont association in sample 1 /986 /2-4,8 m above the base comprises the following species: Belodella resima (Phi I i p, 1965), Hindeodella equidentata (Phi I i p, 1966), H. priscilla S tau f f e r, 1938, Icriodus fa/ax fa/ax Car I s, 1975, I. rectangular is C a r I s & G and I, 1969, I . huddlei curvicauda C a r I s & G and I, 1969, Panderodus uni-costatus (Branson & M chI, 1933), Pandorinellina optima (M o s k a I en k o, 1966), Pedavis brevicauda Murphy & Matti, 1982, Plectospathodus alternatus W a IIi s e r, 1964, P. extensus Rhodes, 1953, Spathognathodus inclinatus wurmi R i s c hoff & San n em ann, 1958. The following taxa are present 2,3 m above the base in sample le: Belodella resima (Phi I i p, 1965), B. triangu/m is (Stauffer, 1940), Plec-tospathodus a/ternatus W a IIi s e r, 1964, P. extensus Rhodes, 1953, Spathognathodus inclinatus inc/ina-Ius (Rhodes, 1953). Sample 1p and 992 /10 contain the following species 1,8 m above the base: Belo-della resima (Phi I i p, 1965), B. triangularis (Stauffer, 1940), Hindeodel/a equidentata (Phi I i p, 1966), H. priscilla Stauffer, 1938, Icriodus angustoides bidellfatus C a r I s & G and I, 1969, Neoprioniodus bicunatus (Branson, Me hI, 1933), Ozarkodina typica denckmanni Z i e g I e r, 1956, Pandorinellina rna-sara (Schon I au b, 1980), P. steinhomensis remscheidensis (Z i e g I e r, 1960), P. steinhomensis eostein-hornensis (W a IIi s e r, 1964), Plectospatlwdus alternatus W a IIi s e r, 1964, P. extensus Rhodes, 1953, Spathognathodus inclinatus wurmi B i s c hoff & San n em ann, 1958. There are only two species 1 m above the base in sample I : Pandorinellina steinhomensis remscheidensis (Z i e g I e r, 1960) and Pelekysgna-thus serratus elongatus C a r I s & G a n d I, 1969. The following conodonts were found in sample 1 v, 0,9 m above the base: Belodella triangularis (Stauffer, 1940), Hindeodel/a equidentata (Ph i I i p, 1966), H. pris-cilla Stauffer, 1938, Ozarkodina media W a IIi s e r, 1957, Pandorinellina steinhornensis remscheidensis (Ziegler, 1960), Spathognathodus inclinatus wurmi Bischoff&Sannemann, 1958. The following conodont association was found in samples 1 and 991 /9 -0,8 m above the packet base: Belodella devonica (Stauffer, 1940), B. resima (Philip, 1965), B. triangularis (Stauffer, 1940), Hindeodellapriscil/a Stauffer, 1938, Icriodus postwoschmidti M a s h k ova, 1968, I. rectangular is CarIs & G and I, 1969, Neoprioniodus bicurvatus (B ranson & Me hI, 1933), N. excavatus (Branson & Me hI, 1933), Oneo-thodus beckmanni B i s c hoff & San n em ann, 1958, Ozarkodina typica denckmanni Z i e g I e r, -1956, Panderodus unicostatus (Branson & Me hI, 1933), Pandorinellina masara (Schon I au b, 1980), P. stein-hornensis remscheidensis (Z i e g I e r, 1960). The following association was found in the packet base of the conodont with a substrate (samples - · 1, Ia, 1129b): Belodella devonica (Stauff e r, 1940), B. resima (Phi-1 i p, 1965), B. triangularis (Stauffer, 1940), Hindeodella equidentata (Phi I i p, 1966), H. priscilla S t a u f f e r, 1938, Jcriodu s eolatericrescens M a s h k o v a, 1968, I oriodus postwoschmidti M a s h k o v a, 1968, I. rectangularis CarIs & G and I, 1969, I. angustoides alcoleae Wed dig e, 1977, /. woschmidti hesperius K I a p per & Murphy, 1974, Neoprioniodus bicurvatus (Branson & Me hI, 1933), N. ex-ca!•arus (Branson & Me hI, 1933), Oneothodus beckmanni B i s c hoff & San n em ann, 1958, Ozar-

5 Geologica Balcanica, 4 65

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tec

ge. The index b al5o accompanied by the following species: Pandorinellina stcinhornensis eosteinhorncnsis (W a 11 is e r, 1964), P. stcinhornensis remsclzeidensis (Zieger, 1960). These species have larger range than the index. Together with the index species also P. rna-sara (Schon I au b, 1980) appears. The latter can be still found in the above lying zone.

N o t e s. The conodont zone Ligonodina e/egans detorta, lying immediattly below, has not been established so far in Southwest Bulgaria for lack of conodonts. It has been established (Jeppson, 1988) that the lower boundary of J. woschmidti zone in Cze-choslovakia lies in Pridoli of Silurian. However, in Southwest Bulgaria this lower boun-dary of the same zone i' both related to the simu1taneous appearance of the index spe-cies and P. masara (S c h on l a u b, 1980). The fact that in Czecho~lovakia the index specie-s of the zone of the same name appeals before P. masara, in comrast to Bulgaria, gives me grounds to consider that lower boundary of the Bulgarian zone lies in Loch-kovian.

Dis t rib uti on. This zone is proved for two of the sections studied - near peak Zemen and Del. The zone comp1ises the thin-layered light-grey limestones and light-green argillites of the lower 65 m of packet 1 and of the bottom 1 m of packet base 2 in the section near Mount Zemen. In the section near Mount Del the zone comprises the thick-layered limestones of the lower 21 m of packet 1.

C o r r e I a t i o n s. 1. woschmidti Range-Zone has a lot of elt.:ments in common with the zone of the same name in the utratotype in Rhenish Slate Mountains- Hiilng Hou-sen Beds and in the stratotype of Lochkovian (Barrandian-Radotin Limestone). I. wosch-midti conelates with the same zone in Podoliya (M a III K o B a, 1970).

Icriodus postwoschmidti Range-zone

Nomen cIa t u r e. The zone is introduced here. It is synomynous to rectangularis zone (Spas so v, 1971), established in the sections near Zemen, the village of Elovitsa, the village of Gorna Vrabca in the same region in Southwest Bulgaria.

S t rat i graph y. The lower boundaty of the zone can be traced according to the first appea1ance of the index species- P. postwoschmidti Mash k ova, 1968, which coincides with the disappearance of the index species of the bdow-lying zone. The zone is based on the local range of ii.S index species, which coincides with that of the following species: Icriodus angustoides bidentatus CarIs & G and 1, 1969, I. eolatericrescens Mash k ova 1968, /. woschmidti hesperius K 1 a p per and Murphy, 1974, I. an-gusto ides alco/eae CarIs, 1969. The following spfcies also appear in the range of this zone: /. angustoides castilianus Carls. 1969, I . rectangu/aris Carls & G and I, 1969, but are spread even after it. The species Pandorinellina masara (S c h on l au b, 1980) and P. steinhornesis eosteinhornensis (Wallis e r, 1964), P. steinhornensis remscheiden-sis (Z i e g I e r, 1960) are still present. The latter two species disappear immediately under the upper zone boundary.

Dis t rib uti o c. The zone comprises the nodular limestones and greish-green al-gillites of the lower 2,3 m of packet 1 in the section near the village of Gorna Vrabca; the thick-layered limestones of packet 2 in the section near Zcmen and the solid thick-layered limesto . ~ es from the 21st m to the 30th m of packet 1 in the section near Del. ·

C o r r e 1 at i on. !. postwo schmidti correlates with the lower parts of "Cortkovski horizont" and with the upper parts of "Bor5tovski horizont" in Podoliya, where M a s h-k ova (1970) distinguished a local zone /. eolatericrescens. The zone can also be corre-lated to: Luesma Beds- die y- Celt Iberian- Spain (Car 1 s & G and I, 1969); "eA." Limestone in the Seeberg region of the Karawanken Alps in Southern Austria (S c h u 1-z e, 1969). According to the American zonation the first Lochkovian zone is hesperius. Species /. postwoschmidti Mash k ova, 1968, is not established in America. In the sec-tions studied in Southwest Bulgaria the index species - /. postwoschmidti and I. wosch-

68

midti hesperius of the zone of the same name, are established in the general zonal asso-ciation, which l use as an argument for remote correlations with North America.

Icriodus /iuddlei curvicauda - Polygnathus dehiscens Interval-zone

Nomen c 1 at u r e. This zone is first introduced as a biointerval in the present work. Approximately it corresponds to the sum of the following zones: curvicauda, tringonica, pesavis (Spas so v, 1971) established in Southwest Bulgaria.

Stratigraphy. The lower boundary of the biointerval zone is defined on the first appearance of I. huddlei curvicauda Car 1 s & G and I, 1969. This species extends its range above the upper boundary of the zone. The species, whose range is only within this zone, but were established only in one section, are: Pedavis brevicauda Murphy & Matti, 1982; Pandorinellina optima (M o s k a I en k o, 1966). The upper boundary of the zone is determined on the first appearance of P. dehiscens Phi I i p & Jackson, 1967. I. angustoides castilianus Car 1 s, 1969 and its distribution appears under the up-per boundary of this zone. Transitional species for this zone are: I. rectangularis Car 1 s & G and I, 1969, Pandorine/lina masara (S c h 6 n 1 au b, 1980).

D i s t rib uti on. The zone includes the nodular limestones and greish-green argil-lites except for the lower 2,3 m of packet 1 in the section near the village of Gorna Vrab-ca, the nodular limestones and greyish-green atgillites from the base of packet 2 up to the end of the section near Del.

C o r r e 1 a t i on s. In the sections studied by me there are some species of the zo-nal associations which were used by Z i e g 1 e r (1971) to differentiate 2 zones within the stratigraphic interval between the first appearance of I. huddlei curvicauda and the first appearance of P. dehischens. This necessitated a larger range of the biostratigraphic zone and at correlation with the European zonal conodont subdivision (Z i e g 1 e r, 1971) the inclusion of zone I. huddlei curvicauda, I. rectangularis, I. angustoides angustoides and zone I. huddlei curvicauda, I. huddlei huddlei.

At comparing of the biointerval zone with the American conodont zones it was estab-lished that in the Bulgarian sections the definitive species and the associated species, used for differentiation of zones eurekaensis, delta and pesavis, were not available. In the Bul-garian zone there arc species present which makes it almost comparable with the total of the following zones: sulcatus and sulcatus n. subsp. (K I a p p e i & Johnson, 1977). These zones have bten established in Central Nevada, Yukon, Western North America, East Australia and Centrai Europe (Germany, Spain) (K 1 a p p e r & Z i e g 1 e r, 1979).

Polygnathus dehiscens dehischens Range-zoue

Nomen c 1 at u r e. The zone is introduced in the preH.nt paper. Stratigraphy. The lowtr boundary of the zone is traced according to the first

appearanle of the index spc,cies- P. dehiscens dehiscens Phi 1 i p & Jackson, 1967, whose range i> within the limits cf zone. Together with it in the base of ihe zone the fol· lowing species apptar: P. dehiscens abysus Maw so 11, 1987, Icriodus bilatericrescens Z i e g I e r, 1956, I. steinachensis A I- Raw i, 1977, Pandorinellina steinhornensis stein-hornensis (Ziegler, 1956), P. steinhornensis miue (Bultyock, 1971), P. steinhor-nensis terre/i (S c h u I z e, 1968), which are also spread even above its upper boundary. I. fa/ax fa/ax CarIs & G and l, 1969 and P. masara (Schon 1 au b, 1980) are met in the below lying biointerval zone and their distribution is restricted with the zone consi-dered. A transitional species of this zone is l. huddlei curvicauda Car 1 s & G and 1, 1969. . D i s t r i but i on. The zone comprises the nodular limestones, greyish-gteen argil-

htes and siltstones from the lower 5, 7 m of packet 3 in the section near the village of Gorna Vrabca.

Co r r e 1 a t ion. The wide spread of the index species of zone P. dehiscens dehiscens

69

Phi I i p & Jackson, 1967 is a sound criterion for the international correlation. The Bulgarian zone is comparable with Conodont Bereich X- Princeps Limestones- Harz Mountain (W a IIi s e r, 1964); Schichtpaket d 4a- Celt Iberian- Spain (CarIs & G and I, 1969) ; Icriodus bilatericrescens- Spathognathodus steinhornensis- Po/ygnatht;s Fauna (Z i e g I e r, 1971) - Princeps, Zorgensi s and Schonauer Lime-stone in the Rh, -nish sc;liefergebirge and Harz Mountain. P. dehiscens Range-Zone COJrelates with dehis-cens complex in the USSR (MalliKosa, CHhf11pesa, 1980; MalliKosa, Co-6ones, 1980; MalliKosa, AneK:HHa, 1981). The Bulgarian zone correlates with the zone of the same name in North America, K I a p-per&Johnson (197~). Klapper&Ziegler (1979).

Polygnathus gronbergi Range-zone

Nomen cIa t u i e. 1'he zone is introduced in the present study. Thi s Taxon-Range-Zone is d .a racterized by the range of the index species- P. gron-

bergi K I a p p e r & J o h n s on, 1975. The other species which have cne and the same rangf' as that of the index species an: P. perbonus (Phi I i p, 1966), I. fusiformis CarIs & G a n d I, 1969, I. claudiae K I a p p e r, 1980, I. culicellu s culicellus (B u It y n c k, 1976). The species whose distribution starts in this zone but extends beyond it are: I. al-ternatus Bran so n & Me h 1, 1933, I. huddlei celtibericus C a r I s & G and I, 1969, f. corniger Witt ek indt, 1966, I. nevadensis John s on&Klapper, 1981, I. cor-niger ancestralis Wed dig e, 1917. The following species have appeared in the below lying zone but disappear at the "nd of this zone : P. dehiscen s abysus Mawson, 1987, /. stei-nachensis A I - R a w i, 1977. The following species are transitional for thi s zone: I. bi-latericrescens Z i e g I e r, 1956, Pandorine/lina steinhornensis telleri (S c h u I z e, 1968), P. steinhornensis steinhornensis (Z i e g It' r, 1956).

D i s t r i but ion. The zone compri ses thin-layered limestones, greyish-green argil-lites and siltstones 0,5 m thick in packt t 3 of the section near the village of Gorna Vrab-ca; the alternation of greyish-green nodular limestones and greyish-green argillites in pa-cket 2 and the alternation of light-grey plate limestones and greyish-yellow argillites of pa-cket 1 in the section near Dalboki Dol; the thin-layered, light-grey, micro-grained lime-stones, interbedded by light-green argillites of packet 4 in the section along the Bela Voda valley; conglomerate fragments in packt:t 4 of the section along the western slopt: of Dal-boki Dol; greyish-yellow argillaceous limestones and greyish-green argillites of packet 2 in the section near the village of Mureno; greyish-green argillites bearing sparse reddish nodule s of limestones from the lower 4 m of packet 1 in the section near Kolina Mahala.

Co r reI at i o n s. The Bulgarian zone P. gronbergi correlates with the zone of the same name established in North America and Europe (K I a p per & John s on, 1977; Weddige&Ziegler, 1977; Klapper&Ziegler, 1979) and with P. perbonus zone established in the USSR (M a lli K o B a H Co 6 one B, 1980; M a lli K o sa, C H H-rH.pesa , 1980), in Australia (Mawson, 1987) and in China (Wang&Ziegler, 1983).

Polygnathus laticostatu s Range-zone

No men cIa t u r c. The zone is introduced hete. Stratigraphy. The zone is characterized by the range of the index species-

P. latico status K I a p per & Johnson, 1975. The lowe r boundary of this zone is de-termined on the first appearance of the index species, and the apptarance of /. becmanni sinuatus K I a p per, Z i c g I e r & Mash k ova. 1978 . With respect to the sections studied this species is spread only within the range of the zone. The lower boundary is also determined on th e basi~ of the fi 1 st appearance of P. inl'ersus K I a p per & John-s on, 1975. The latter i

Dis t rib uti on. The zone comnriscs greyish-green a rgillite s with rare reddish nodules built up of limestones ~ ·rom the 14th m up to the 20th m of packet 1 in the sec-tion near Kolina Mahala ; nodular limestones with rare interbeds of greyish-green argil-lites of packet 3 in the section near the village o f Mureno .

Cor r c l at ion s. P. /atico statu s R a nge-zone m ay both correlate with the zone in Euro pe (K I a p per, Ziegler & Mas h~k ova. 1987) and with P. inversus esta bli-shed in North Americ

in the section along DiUboki Dol. The lower part of the zone is corroborated in section I near Vuka shinova Mahala, where it includes the barytized limestone of packet 8.

References

CarI s, P., G and I, J. 1969. Stratigraphie und Conodonten des Unter-Devons der Ostlichen Iberischen Ketten (NE - Spanien). - N. lb. Geol. Paliiont. Abh .. 132, 2; 155-218.

J e p p s son, L. 1988. Conodont biostratigraphy of the Silurian - Devonian boundary stratotype a t Klonk, Czechoslovakia. - Geol. et Palaeont., 22; 21-31.

K I a p per, G. , Johnson, D . B. 1977. Lower and Middle Devonian conodont sequence in Central Neva-da. -In: M. A. Murphy et al. Western North America: Deronian. - Univ. Calif. Reverside, Camp. Mus. Contr. , 4; 33-54.

K I a p p e r, G. , J o h n so n, J. G. 1980. Endemism and dispersal of Devonian conodonts. - J. Paleont., 54, 2; 400-455.

K I a p per, G ., Z i e g I e r, W. 1979. Devonian conodont biostratigraphy.- Spec. Pap. Paleont. , 23; 199-244. K I a p per, G., Z i e g I e r, W., Mash k ova, T. 1978. Conodonts and correlation of Lower- Middle

Devonian boundary beds in the Barrandian area Czechoslovakia. - Geol. et Palaeont. , 12; 103-115. Mash k ova, T. V. 1979. Conodont zones of the Lower Devonian in the USSR.- Geol. et Palaeont., 13;

97-102. Mawson, R. 1987. Early Devonian conodont faunas from Buchan and Bindi, Victoria, Australia. - Pa-

leontolog'y, 30, 2; 251-297. S c h u I z e, R. 1968. Die Conodonten aus dem Palaozoikum der mittelercn Karawanken (Secberggebiet).-

N. J. Geol. Paliionf., Abh.. 130, 2; 133-245. Spas s o v, C hr. 1971. Die Conodontenchronologie des Unterdevons im Mittelteil der Balkanha Ibinscl.

- H16. reo.1. uncm., cep. cmpanuup. 11 .4umo.4., 22; 5-14. W a IIi s e r, 0 . 1964. Conodonten des Silurs. - Abh. hess. L.- Amt Boden{orsrh .. 41 ; 1-106. Wang, C., Z i c g I e r, W. 1983. Conodonten aus Tibet.- N. Jb. Geol. Paliiont., Mh., 2; 65-79. Wang, C., Z i e g I e r, W. 1983. Devonian conodont biostratigraphy of Guangxi, South China and corre-

lation with Europe.- Geol. et Palaeont., 17; 75-107. Wed dig e, K. , Z i e g I e r, W. 1977. Correlation of Lower /Middle Devonian boundary beds.- News!.

Stratigr., 6, 2; 67-84. Zag o r i! e v, I., Bon i! ev a, I. 1988. Indications of Devonian basic volcanism in Southwest Bulgaria.-

Geolo?ica Bale., 18, 4; 55-63. Z i e g I e r, W. 1971. Conodont stratigraphy of the European Devonian. - Geol. Soc. America, Memoir 127;

227-278. b 0 H 'I e B a, .JII. 1987. KOHO,n:OHTH OT Bpa6'faHCKaTa CBHTa (,n:eBOHCKa CHCTCMa) B 06JiaCTTa KpaHll.lC, J0ro3a-

na,n:Ha libMapHll.- Cn. EMz. zeo,z. o-«o, 48, 2; 117-125 . .LJ: H H K 0 B a, lf., 3 a f 0 p 'feB, .JII., U aRK 0 B, U:. 1987. BJaHMOOTRO WCHHll MeJK,n:y CTapoaJinHi'ICKHTe ,n:e-

cj>opMal{HH B TpbHCKJf ll aHTHKJIHHOpuil:.- reomeKm., meKmo11oifju1. , 11 zeoouu. , 20; 33-48. MaIn K o B a, T. 1970. 06 yTo'IHeHHH o6DeMa 30Hbt woschmidti B Tio,n:orrHH.- Pon.1. AH CCCP, 190, 3;

654-657. M a Ill K 0 B a, T., An e K H H a, Jl. 1981 . .[(peBHeil:wHe OOJIHTHaTyCbl 3apaswaHCKOrO xpe6Ta- DOKa3aTeJIH

rpaHHUbt IDJJKHero-