UPPER ORDOVICIAN BRACHIOPODS FROM KAZAKHSTAN 



19 



626 8223a, 8223b 



843 



100b 8221 A 



Devonian 



Fig. 6 A, general view of the Anderken Formation at the Anderkenyn-Akchoku section, showing informal lithostratigraphic units discussed in the text and 

 the position of brachiopod localities. B, view of large complex carbonate buildup at Akchoku Mountain in the upper part of the Kujandysai section. 

 Photographs by Igor Nikitin. 



Unit 5. Massive micritic limestone forming the core of the carbon- 

 ate mud-mound at the top of the mountain, about 30 m thick. 



The upper part of the Anderken Formation outcrops along the 

 north-eastern slope of Buldukbai-Akchoku Mountain. It includes: 



Unit 6. Laminated, dark green siltstone up to 70 m thick with storm 

 beds of calcareous sandstone rich in brachiopod coquinas about 10- 

 15 cms thick and crinoid columnals. The top is a characteristic bed of 

 laminated brownish-violet siltstone about 0.5 m thick overlain by 

 polymict conglomerate of the Dulankara Formation (Fig. 7B). The 



unit contains numerous coalified plant remains of Akdalaphyton 

 caradoci concentrated on several bedding surfaces, brachiopods of 

 the Sowerbyella-Mabella Association (Samples 8229, 8230) and the 

 echinoderms Clivosocystis sp., Digitocrinus levis and Ristnacrinus 

 bifidus Stukalina. 



Locality 5. Tesik River 



This locality is on the southern side of the River Tesik about 1.5 km 

 upstream of the bridge crossing the river on the highway from 



