U ISLAND LIFE 



PART I 



an outlet to the Arctic Ocean between the Ural range and 

 Finland. South of the Alps there was probably another 

 sea, which may have communicated with the northern one 

 just described, and there was also a narrow strait across 

 Switzerland, north of the Alps, but, as might be expected, 

 in this only marls, clays, sandstones, and limestones were 

 deposited instead of true chalk. It is also a suggestive 

 fact that both above and below the true chalk, in almost 

 all the countries where it occurs, are extensive deposits of 

 marls, clays, and even pure sands and sandstones, charac- 

 terised by the same general types of fossil remains as the 

 chalk itself. These beds imply the vicinity of land, and 

 this is even more clearly proved by the occurrence, both 

 in the Upper and Lower Cretaceous, of deposits containing 

 the remains of land-plants in abundance, indicating a rich 

 and varied flora. 



Now all these facts are totally opposed to the idea of 

 anything like oceanic conditions having prevailed in 

 Europe during the Cretaceous period ; but they are quite 

 consistent with the existence of a great Mediterranean sea 

 of considerable depth in its central portions, and occupying 

 either at one or successive periods, the whole area of the 

 Cretaceous formation. We may also note that the Maes- 

 tricht beds in Belgium and the Faxoe chalk in Denmark 

 are both highly coralline, the latter being, in fact, as com- 

 pletely composed of corals as a modern coral-reef ; so that 

 we have here a clear indication of the source whence the 

 white calcareous mud was derived which forms the basis 

 of chalk. If we suppose that during this period the 

 comparatively shallow sea-bottom between Scandinavia 

 and Greenland was elevated, forming a land connection 

 between these countries, the result would be that a large 

 portion of the Gulf Stream would be diverted into the 

 inland European sea, and would bring with it that abun- 

 dance of Globigerinse, and other Foraminifera, which form 

 such an important constituent of chalk. This sea was 

 probably bordered with islands and coral-reefs, and if no 

 very large rivers flowed into it we should have all the con- 

 ditions for the production of the true chalk, as well as the 

 other members of the Cretaceous formation. The products 



