HISTORICAL GEOLOGY 111 



Asa Gray had received from Darwin an advance copy 

 of the book that was to revolutionize the thought of the 

 world, and at once wrote for the Journal a Review of 

 Darwin's Theory on the Origin of Species by means of 

 Natural Selection (29, 153, 1860). This is a splendid, 

 critical but just, scientific review of Darwin's epoch- 

 making book. Evidently views similar to those of the 

 English scientist had long been in the mind of Gray, for 

 he easily and quickly mastered the work. He is easy on 

 Dana's Thoughts on Species, which were idealistic and 

 not in harmony with the naturalistic views of Darwin. 

 On the other hand, he contrasts Darwin's views at length 

 with those of the creationists as exemplified by Louis 

 Agassiz, and says "The widest divergence appears." 



Gray says in part : 



"The gist of Mr. Darwin's work is to show that such varieties 

 are gradually diverged into species and genera through natural 

 selection; that natural selection is the inevitable result of the 

 struggle for existence which all living things are engaged in; 

 and that this struggle is an unavoidable consequence of several 

 natural causes, but mainly of the high rate at which all organic 

 beings tend to increase. 



Darwin is confident that intermediate forms must have 

 existed; that in the olden times when the genera, the families 

 and the orders diverged from their parent stocks, gradations 

 existed as fine as those which now connect closely related species 

 with varieties. But they have passed and left no sign. The 

 geological record, even if all displayed to view, is a book from 

 which not only many pages, but even whole alternate chapters 

 have been lost out, or rather which were never printed from the 

 autographs of nature. The record was actually made in fossil 

 lithography only at certain times and under certain conditions 

 (i. e., at periods of slow subsidence and places of abundant sedi- 

 ment) ; and of these records all but the last volume is out of 

 print; and of its pages only local glimpses have been obtained. 

 Geologists, except Lyell, will object to this, some of them 

 moderately, others with vehemence. Mr. Darwin himself admits, 

 with a candor rarely displayed on such occasions, that he should 

 have expected more geological evidence of transition than he 

 finds, and that all the most eminent paleontologists maintain the 

 immutability of species. 



The general fact, however, that the fossil fauna of each period 

 as a whole is nearly intermediate in character between the 

 preceding and the succeeding faunas, is much relied on. We 



