388 W. F. Hume — Notes on Russian Geology. 



Cretaceous basin. At the same time most of the genera are the 



same as those occurring in the English Chalk, and the results may 



be analysed as follows : 



In Western Europe. 



( Ostrea vesicularis ... "Whole Upper Cretaceous. 



Common or mixed \ ,, JlabelUformis ... Turonian and Senonian. 



forms ... ...\ Spondylus spinosus ... Ditto ditto. 



( Parasmilia centralis ... Ditto ditto. 



Echinocorys ovata ... Belcynnitella mucronata Zone. 



Terebratula carnea ... Do.andMicr. cor-anguinum Zone. 



c, ■ t 1 Manas pumilus ... Belemnitella mucronata Zone. 



Senoman forms ... < „ / f ,, , j^... 



Belemnitella mucronata Ditto. 



Pecten undulatiis ... Marsupites Zone. 



Many Ventriculites. 



And probably most of the Fish remains ... ... Beryx, Cor ax, Ischyodon, etc. 



/-, „ • n { Cidaris vesiculosa ... PwfeM <?s«er and Chloritic Marl. 



Cenomaman forms ... < <., i t t t, t 



{^berpula gordialis ... Pecten asper. 



It will be seen from the above list that by far the greater number 

 of the fossils obtained belong to the higher beds of the Ui^per 

 Cretaceous in W. Europe, and it is therefore, on the whole, perhaps 

 advisable to conclude that the "White Chalk and Chalk Marl represent 

 a Senonio-Turonian series in which divisions are not sharply marked 

 oif as with us. 



Summing up then, we may conclude that the Cretaceous beds are 

 cropping out in the following order from S. to N. : 



1. Chalk (white and soft, in N. Kharkoff" Government). 2. Chalk 

 Marl (in S. of Kursk Government). 3. The phosphoritic grits of 

 Kursk, which have been shown to be Cenomanian by the Russian 

 geologists, and which crop out some five versts N. of the above 

 town. A few words may also be of interest as to the work done 

 •with regard to these beds in the Governments on the N.E. and E. 

 of the Kharkoff Government. 



In the Saratov Government Prof. SintzofF has noticed two upper 

 Cretaceous divisions — a sandy and a marly or chalky division; 

 passing into one another by gradual lithological change ; he divides 

 the latter again into (1) Chalk; (2) Chalk Marl; (3) Sponge beds, 

 with numerous remains of sponges. (This has not been met with 

 in the Kharkoff bore.) The same Professor has again remarked 

 for the Simbirsk Government that there are two main divisions, 

 viz.: Chalk and Chalk Marl, inseparable from one another, both 

 on palasontological and stratigraphical grounds. Below this occurs 

 glauconitic chalk, with phosphatic nodules. In the above views 

 Professor Lagusen concurs. Professor Sintzoflf has also come to the 

 conclusion that the fauna of these beds is a mixture of Senonian and 

 Turonian forms. Professor Lagusen has remarked that the fauna of 

 Simbirsk is mainly Senonian, but at the same time Turonian forms 

 occur, and this condition holds for other Governments, wherever 

 studied (Voronesh, Don Cossack country, Kursk, Kharkoff, and 

 Ekaterinoslav). 



Prof. Borusak also has divided these beds into White chalk, Chalk 

 JTarl, and Glauconitic marlj^ sandstones. For the Kursk Govern- 

 ment Hofmann has shown that the famous phosphorite grit or 



