C. Schuchert — Russian Carboniferous and Permian. 33 



origin) ; Marginifera 8. Pelecypods also common and 

 of the ordinary Upper Carboniferous types. Of cephalo- 

 pods, Agathiceras uralicum, Pronorites cyclolobus uralen- 

 sis, P. postcarbonarius. Trilobites, Grrjjithides roemeri 

 and G. gruenewaldti. 



Productus cora zone (C|), about 70 meters thick in Timan and 

 100 in southern Ural. The most abundant fossil is P. 

 cora. Other brachiopods are Dielasma, 4 species (bovi- 

 dens) ; Camarophoria 4 ; Spiriferina 2 ; Spiriferella sar- 

 ance, Spirifer cameratus, 3. condor, S.fasciger, S. mar- 

 coui (goes no higher), Derbyia regidaris, D. crassa, 

 Meekella striaticostata and 3 other species ; Chonetes 

 mesoloba, C. granulifera, C.flemingi, C. variolata, Aulo- 

 steges, Productus boliviensis and 21 other forms, Mar- 

 ginifera uralica and 4 other forms. Corals are rare, 

 especially the compound forms so common both above 

 and below. Archimedes rare. Large Fusulina verneuili. 

 Griffithides scitula. 



Omphalotrochus zone (Cj-b). This zone and the one below 

 have a united thickness of about 70 meters. Most abun- 

 dant fossil Omphalotrochus whitneyi. Of brachiopods 

 there, are Dielasma itaitubense, Camarophoria 3, /Spiri- 

 fer marcoui, Derbya crassa, D. regularis, Meekella 

 striaticostata, Aulosteges, Productus nebrascensis, P. 

 cora, P. 10 species, Marginifera uralica. Corals very 

 abundant ; this zone in the Urals is 12 meters thick. 



Spirifer marcoui zone (C-Ja). 



Has an abundance of &. marcoui and corals. 



Middle Carboniferous, or Moscowian (Co), about Miatschkowo. 



1. Greenish white fragmental limestone, *3 meter thick. 



2. Greenish compact argillaceous limestone, '1 meter thick. 



3. Yellow dolomitic limestone, 2-J to 3 meters thick. 



Abounds in fish teeth and plates of Cladodus, Dactylochis, 

 Deltodus, Ostinaspis^ Poecilodits, Polyrhizodus, Psepho- 

 dus, Psammodus, and Solenodus. Also Productus semi- 

 reticulatus. 



4. Grayish compact limestone, 1-J to 2 meters thick. 



5. White granular soft flaggy limestone, 2 to 3 meters thick. 



Has a normal marine fauna. Those preceded by 1 are 

 the characteristic species. Has many of the fishes found 

 in 3, and Cymatodus, Helodus, Orodus, Petalodus, and 

 Tomodus. Also Nautilus mosquensis, Euomphalus 

 pentangulatus, E. marginatus, Macrocheilus ampidlace- 

 ous, Allorisma regulare, Conocardium uralicum, Pro- 

 ductus cora (riparius), P. lineatus, 1 P. semireticidatus, 



Am. Jour. Sci.— Fourth Series, Vol. XXII, No. 127.— July, 1906. 

 3 



