168 LIFE ON THE EARTH. 



zones, most probably here and there diversified by 

 primitive islands, whose situation, however, and con- 

 stitution are merely conjectural, till we arrive at 

 the series of Wenlock rocks in the Malvern hills. 

 Here is proof of land situated where now is the 

 ridge of the Worcester Beacon ; land from which fell, 

 into the sea of that period, rocky fragments precisely 

 the same in nature as the variable Syenites of that 

 ridge ; fell into tranquil and slightly agitated water 

 of small depth, and were there cemented together with 

 Corals, Crinoids, Shells and Trilobites, a venerable 

 and interesting mark of the ancient limit of the old 

 and populous sea, against the old perhaps uninha- 

 bited land. Accustomed, in this way, to regard the 

 northern seas of our time as the shrunk and rami- 

 fied remainders of wider tracts of ocean, and the 

 lands as amplified by comparatively modern desicca- 

 tion round primitive peaks and ridges, we naturally 

 turn to consider whether the forms of life in the 

 sea manifest any special affinity to the fossils of the 

 neighbouring tracts from which it has withdrawn ; 

 and in what degree the plants and animals which 

 now cover the land are related to those which 

 occupied smaller spaces in the same regions. 



Taking for a favourable illustration the Germanic 

 Ocean, and comparing its Mollusca with those of the 

 adjoining Pleiocene Crag, on the eastern coast of 



