40 THE PAST CONDITION 



of the body would float and drift away altogether, ultimately 

 tug (he sea, and perhaps becoming destroyed. The 

 jaw becomes covered up and preserved in the river silt, 

 and thus it comes that we have such a curious circumstance 

 as that of the lower jaws in the Stonesfield slates. So 

 that, you see, faulty as these layers of stone in the earth's 

 crust are, defective as they necessarily are as a record, 

 the account of contemporaneous vital phenomena presented 

 by them is, by the necessity of the case, infinitely more 

 defective and fragmentary. 



It was necessary that I should put all this very strongly 

 before you, because, otherwise, you might have been led 

 to think differently of the completeness of our knowledge 

 by the next facts I shall state to you. 



The researches of the last three-quarters of a century 

 have, in truth, revealed a wonderful richness of organic 

 life in those rocks. Certainly not fewer than thirty or 

 forty thousand different species of fossils have been dis- 

 covered. You have no more ground for doubling that 

 these creatures really lived and died at or near the places 

 in which we find them than you have for like scepticism 

 about a shell on the sea-shore. The evidence is as good 

 in the one case as in the other. 



Our next business is to look at the general character of 

 these fossil remains, and it is a subject which it will be 

 requisite to consider carefully ; and the first point for us 

 is to examine how much the extinct Flora and Fauna 

 as a whole disregarding altogether the succession of 

 their constituents, of which I shall speak afterwards 

 diller from the Flora and Fauna of the present day; 

 how far they differ in what we do know about them, 

 leaving altogether out of consideration speculations based 

 on what we do not know. 



I strongly imagine that if it were not for the peculiar 

 appearance that fossilized animals have, any of you 

 might readily walk through a museum which contains 

 remains mixed up with those of the present forms 

 of life, and I doubt very much whether your uninstructed 

 eyes would lead you to see any vast or wonderful difference 

 between the two. If you looked closely, you would notice, 

 in the first place, a great many things very like animals 

 with whieh you are acquainted now : you would see differ- 

 ences of shape and proportion, but on the whole a close 

 similarity. 



