I UK CRETACEOUS SYSTKM 521 



to imliratr tin- estuary of a river, which was probably that 

 tlouiug out of the Wealden lake. 



It is generally admitted that during the earlier part of this 

 epoch, i.e. during Wealden and Neocomian times, land existed in 

 the north-east of France and over Belgium and that it was con- 

 nected with land over the east of England. It is my own opinion 

 that this was a fairly broad tract of land enclosing the Wealden 

 lake and connecting the western land with that of Central Europe. 

 Further, I hold that this isthmus was never broken through till tin- 

 Aptian epoch, when the Northern and Southern Seas met in a 

 strait which passed obliquely across England from Wiltshire to 

 Cambridge and Norfolk. 



We may now turn our attention to the general position and 

 extensions of these Southern and Northern Seas. The former 

 appears to have covered most of Eastern France (south of the 

 Ardennes), and to have stretched eastward through Switzerland 

 and Italy across the southern part of Austria and the Danubian 

 provinces to the Black Sea and the Crimea. The Northern Sea 

 occupied a large part of what is now the Arctic Ocean and extended 

 southward in two great gulfs, one on each side of the Fenno- 

 Scandian land. 



The western gulf touched the north of Scotland (Caithness and 

 Aberdeen), and seems to have passed southward through the North 

 Sea area into Yorkshire and Lincolnshire on the one hand and into 

 Germany on the other. The eastern gulf occupied a large part of 

 Northern Russia, extending southward to the Moscow basin and 

 south-east to the province of Simbirsk ; but near Moscow the sea 

 was shallow, as the zone of Bel. Jasekowi is there represented 

 by sands with plant remains but no marine fossils, so that they 

 seem to be of brackish or freshwater origin. 



The question remains whether there was any water-connection 

 between the extremities of the eastern and western gulf, or wlu-thor 

 Fenno-Scandia was united to the Sarmatian land. So far as tin- 

 similarity of the English and Russian faunas is concerned, that both 

 were derived from the Northern Ocean is sufficient explanation. 

 The only evidence for the theory that the gulfs were otherwise 

 connected is the existence of some deposits of Lower Cretaceous 

 age at Brzezie on the borders of Posen and Poland, where fresh- 

 water beds with Cyrena and Cypris are succeeded by sands and 

 conglomerates which are overlain by clays with Astarte and Exogyra 

 Couloni ; but these bivalves may be of any zonal age, and only 

 indicate the line along which the sea eventually made its way 

 across the space between Hanover and Moscow. 



Having regard to the presence of freshwater deposits of early 



