92 
ISLAND LIFE. 
[part 1. 
and even pure sands and sandstones, characterised 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 any- 
thing like oceanic conditions having prevailed in Europe during 
the Cretaceous period ; but it is quite consistent with the ex- 
istence 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 Maestricht beds in Belgium and the Faxoe 
chalk in Denmark are both highly coralline, the latter being, 
in fact, as completely 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 he diverted into the inland European sea, 
and -would bring with it that abundance of Glohigerinae, 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 conditions for the production of the true chalk, as 
well as the other members of the Cretaceous formation. The 
products of the denudation of its shores and islands would form 
the various sandstones, marls, and clays, which would he de- 
posited almost wholly within a few miles of its coasts ; while 
the great central sea, perhaps at no time more than a few 
thousand feet deep, would receive only the impalpable mud of 
the coral-reefs and the constantly falling tests of Forami- 
nifera. These would imbed and preserve for us the numerous 
echinoderms, sponges, and mollusca, which lived upon the 
bottom, the fishes and turtles which swam in its waters, 
and sometimes the winged reptiles that flew overhead. The 
