16 



L.E. POPOV, L.R.M. COCKS AND I.F. NIKITIN 



Devonian 



1 . Anderkenyn-Akchoku 

 section (west) 

 l-»- 2. Kujandysai section 



4. Buidukbai-Akchoku 

 Mountain 



8. Kotnak mountains 

 SWof Karpkuduk 



Devonian 



7. South side of 

 Karatal river south 

 of Sorbulak spring 300 



6. Burultas 

 valley 



A.-D.A. ,oo 

 F-1041a 

 «■ 818a 

 T.A. 



50 



2 



F-1024b 

 T.A. , 



F-1024 

 Ect. A. 



T.A. 



.-F-1018 



e-F-1018a 



T.A. 



Conglomerate and sandstone, 

 intercalating 



Intercalating sandstone 

 and siltstone with coquina 

 storm beds 



Limestone and siltstone 

 intercalating 



Sandstone, bedded. 



Sandstone, cross-bedded 



Sandstone 



7*TT71 Conglomerate, pebbly, 

 polymict 



Beke Formation 





Sandstone, siltstone 

 and mudstone, graded 



MIDDLE ORDOVICIAN 

 Uzunbulak Formation 



Siltstone and mudstone 



Fig. 3 Columnar sections through the Anderken Formation showing informal units, stratigraphic positions of samples and brachiopod associations: Ect. A.- 

 Ectenoglossa Association, T. A., Tesikella Association, M.S. A.. Mabella-Sowerbyella Association. A.-D. A., Acculina-Dulankaretla Association, P.-K. A., 

 Parastrophina-Kellerella Association, Z.-F. A., Zhilgyzambonites-Foliomena Association, G.-B. A, Gastropod-Bivalved Molluscs Association. The 

 numbers of the sections are the same as those on Fig. 1 . 



Unit 3. Coarse- to medium- grained sandstone with mostly 

 subhorizontal stratification, about 40-62 m thick in the Anderkenyn- 

 Akchoku section and up to 97 m thick in the Kujandysai section, with 

 some storm beds of coquinas up to 20 cm thick with concentrations 

 of gastropods and the disarticulated bivalved molluscs Edmondia 

 fecunda Khalfin, Ctenodonta sp. and Orthonota'l sp. (Sample 8 1 30a). 

 Gastropods, bivalved molluscs and the trilobite Eokosovopeltis 

 romanovskyi become increasingly abundant in the flank deposits in 

 the upper 20 m of the unit (Samples 8130, 8134). In the Kujandysai 

 section concentrations of bivalved molluscs occur in the middle part 

 in association with the rare brachiopod Tesikella necopina and the 

 pelmatozoan columnals Clivosocystis clivosus Stukalina and 

 Ordinacrinus punctatus Stukalina (Sample 761 1). 



Unit 4. Medium- to fine-grained sandstone replaced gradually up- 

 wards by siltstone with numerous trace fossils and symmetrical 

 ripple marks. Thickness varies from 22 to 80 m in the Anderkenyn- 

 Akchoku section and is about 28 m in the Kujandysai section. The 

 lower part contains local concentrations of the coalified plant 

 Akdalaphyton caradoci Senkevich, and gastropod and bivalved mol- 



luscs in association with the brachiopod Tesikella necopina (Sam- 

 ples 8 127-2b, 8 1 29, 8 1 33, 8 1 38). The upper part contains an abundant 

 brachiopod fauna of the Sowerbyella-Mabella Association (Sam- 

 ples 100b, 7613. 8128a, 8128b, 8135, 8137) and the trilobites 

 Dulanaspis laevis anderkensis Chugaeva, Lonchodomas tecturmasi 

 Weber, Pliomerina sp., Remopleurides sp., Styginella macrophtalma 

 Pribyl & Vanek, Bronteopsis extraordinaris Chugaeva, the cystoid 

 and crinoid columnals Clivosocystis clivosus, Digiticrinus levis 

 Stukalina, Ordinaricrinus punctatus Stukalina and Communicrinus 

 communis Stukalina and the starfish Stenaster obtusus (Forbes). 



Unit 5. Limestones varying in thickness from 8 to 98 m forming a 

 chain of carbonate build-ups between the Uzunbulak and the Ashchisu 

 rivers (Fig. 3). The cores of these build-ups rest on a bed of nodular 

 limestone from 2-10 m thick with abundant dasyclad algae 

 Cyclocrinites nikitini Gnilovskaya and Mastopora reticulata 

 Gnilovskaya (Nikitin etal. 1974). A bed of nodular, algal limestone 

 with dasyclad algae is usually present in the interspaces between the 

 carbonate build-ups and contains brachiopods of the Acculina- 

 Dulankarella Association (Samples 100, 8251. 85258), the rare 



