172 LAY SERMONS, ESSAYS, AND REVIEWS. [ IX . 



more ancient seas ; and many kinds of living shell-fish first 

 become known to us in the chalk. The vegetation acquires a 

 modern aspect. A few living animals are not even distinguish 

 able as species, from those which existed at that remote epoch. 

 The Globigerina of the present day, for example, is not different 

 specifically from that of the chalk ; and the same may be said of 

 many other Foraminifera, I think it probable that critical and 

 unprejudiced examination will show that more than one species 

 of much higher animals have had a similar longevity ; but the 

 only example which I can at present give confidently is the 

 snake s-head lamp-shell (Terebratulina caput serpentis), which 

 lives in our English seas and abounded (as Terebratulina striata 

 of authors) in the chalk. 



The longest line of human ancestry must hide its diminished 

 head before the pedigree of this insignificant shell-fish. We 

 Englishmen are proud to have an ancestor who was present at 

 the Battle of Hastings. The ancestors of Terebratulina caput 

 serpentis may have been present at a battle of Ichtliyosauria 

 in that part of the sea which, when the chalk was forming, 

 flowed over the site of Hastings. While all around has 

 changed, this Terebratulina has peacefully propagated its species 

 from generation to generation, and stands to this day, as a 

 living testimony to the continuity of the present with the 

 past history of the globe. 



Up to this moment I have stated, so far as I know, nothing 

 but well-authenticated facts, and the immediate conclusions 

 which they force upon the mind. 



But the mind is so constituted that it does not willingly rest 

 in facts and immediate causes, but seeks always after a knowledge 

 of the remoter links in the chain of causation. 



Taking the many changes of any given spot of the earth s 

 surface, from sea to land and from land to sea, as an established 

 fact, we cannot refrain from asking ourselves how these changes 

 have occurred. And when we have explained them as they 

 must be explained by the alternate slow movements of eleva- 



