394 TF. F. Hume — Notes on Russian Geology. 



We have thus followed Murchison in taking a typical series of 

 localities on the Volga, the evidence showing that the Cretaceous, 

 especially the Upper Wliite Chalk, is strongly developed over a wide 

 superficial area, though never apparently attaining any considerable 

 thickness. 



IV. Leaving the Volga district to the E. the boundary of the 

 Senonio-Turonian basin passes to the N. of the Voronesh Govern- 

 ment, to the N. of the Kursk Government and also through the N. 

 of the Tchernigov Government, resting at Klintsi, on glauconitio 

 ferruginous sands, sandstones and limestones, containing fossils of 

 Cenomanian age. We have thus traced the great central basin 

 (presumably Senonio-Turonian) from all evidence now to hand, 

 showing its junction with the Cenomanian at points widely distant 

 from one another, and the question now arises, How far can this 

 basin be traced to the westward ? At this point we must take 

 advantage of the great Russian text-book, written by Professor 

 Inostranseff, and the evidence he adduces proves that this basin 

 is to be met with almost up to the Russo-Gerraan Frontier. 



In Podolia and Volhynia white Chalk, Chalk Marl, and marly 

 sands, are all met with. 



In the main governments of Poland the same condition of things 

 occurs, but here the Chalk Marl is rich in Turonian fossils, and 

 there would appear to be more sharply defined limits between the 

 Turonian and Senonian as we pass westward. In the Lublin 

 Government (S. Poland) these beds are well developed, being 

 300 to 540 feet thick, and resting directly on glauconitic sands or 

 marls containing Gault fossils. 



The Upper Cretaceous has also a wide extension in the N. of the 

 Government of Grodno, as also in Kovno and Courland, and there 

 seems no reason to doubt that the great Russian Upper Cretaceous 

 area is thus directly united with the Swedish deposit, and is only 

 hidden by a thick series of Tertiary beds. 



Conclusions as to Central and Russian Uppee Cretaceous Basin 

 (Exclusive of Cenomanian). 



1. Its length from E. to W. is almost equal to the greatest breadth 

 of the Russian Empire (over 1200 miles). This is reckoned from 

 the River Vistula, near Lublin, to the River Oural, near Orenboui-g. 



2. Its general breadth may be taken at 200 miles from N. to S. 

 Thus from Kursk to Tzium this breadth is attained. 



3. Its greatest known depth is attained at the town of Kharkoff 

 (1831 feet), thus presenting the greatest thickness of Chalk and 

 Chalk Marl in Europe. This diminishes towards Poland, on the 

 W., where it is 540 feet thick, and toward the Volga, on the E., 

 where it is 200 feet thick. 



4. Its palaeontological contents show it to represent a facies which 

 is not definitely Senonian or Turonian, but is a combination of both 

 (Senonio-Turonian), and that the lithological variations (Chalk and 

 Chalk Marl) have no effect on the character of the enclosed fossils. 



