4 LOWER PENINSULA. 



the correctness of this view, universally believed to be the remains 

 of the animals which perished during this catastrophe, which belief 

 was obstinately held up to the end of the eighteenth century. At 

 that time, with the progress made in natural history, so many facts 

 contradicting this theory had accumulated, that it could no longer be 

 held. It was clearly recognized that the deluge could not account 

 for fossils generally ; that there existed an immense difference in 

 the age of fossils, and that a large number of animal and vegetable 

 creations came and disappeared again, in ^long-continued succes- 

 sion, involving the lapse of spaces of time far exceeding former 

 conceptions of the age of the globe. 



The study of the fossils and of the conditions under which they 

 were found threw an entirely new light on the earth's history. 

 Formerly the fossils were mere objects of curiosity ; now^ they be- 

 came important witnesses to a long series of progressive changes 

 which the earth must have undergone ages and ages before man 

 was created, and before the scriptural deluge could have occurred ; 

 of changes which were rarely sudden reversals of the existing condi- 

 tions, but which were from the beginning and are now in constant 

 quiet action — an endless, shifting motion; destroying here and build- 

 ing up there, with a slowness almost imperceptible, but, in the long 

 lapse of time, astounding in its effects. The attentive study of fos- 

 sils led to the discovery that, in the series of rock beds composing 

 the earth's crust, certain animal forms were confined to a certain 

 definite group of strata, which, in ascending to higher beds, disap- 

 peared gradually or abruptly, and were replaced by new forms ; 

 the same changes were noticed to occur frequently in ascending 

 higher and higher. It was further ascertained, on examination of 

 far remote localities, but built up by an equivalent succession of 

 rock beds, that, in the distribution of fossils throughout the strata, 

 the same order is found to exist — that is to say, the equivalent 

 strata contain in different places the same, or at least very similar 

 fossils. By deduction from this rule, we may infer that strata con- 

 taining the same fossils have the same relative age ; we have in the 

 fossils a standard criterion for the determination of a certain geolog- 

 ical horizon, irrespective of the character of the rock, which may 

 be widely different in remote equivalent beds, and independent of 

 direct observation of the succession of the beds, which may be 

 hidden from view, or be complicated by irregularities, either through 



