88 Prof. A. Gray on Species considered as to 



bevy of admitted derivatives, and its attending species only pro- 

 visionally admitted to that rank, is very closely related to certain 

 species of Eastern Asia, and of Oregon and California — so closely 

 that " a view of the specimens by no means forbids the idea that 

 they have all originated from Q. rohur, or have originated, with 

 the latter, from one or more preceding forms so like the present 

 ones that a naturalist could hardly know whether to call them 

 species or varieties." Moreover there are fossil leaves from 

 diluvian deposits in Italy, figured by Gaudin, which are hardly 

 distinguishable from those of Q. robur, on the one hand, and 

 from those of Q. Douglasii, &c., of California, on the other. No 

 such leaves are found in any Tertiary deposit in Europe ; but 

 such are found of that age, it appears, in North-west America, 

 where their remote descendants still flourish. So that the pro- 

 bable genealogy of Q. rohur, traceable in Europe up to the 

 commencement of the present epoch, looks eastward and far 

 into the past on far distant shores. 



Q. Ilex, the Evergreen Oak of Southern Europe and Northern 

 Africa, reveals a similar archaeology ; but its presence in Algeria 

 leads DeCandolle to regard it as a much more ancient denizen 

 of Europe than Q. robur; and a Tertiary Oak (Q. ilicoides), 

 from a very old Miocene bed in Switzerland, is thought to be 

 one of its ancestral forms. This high antiquity once established, 

 it follows, almost of course, that the very nearly related species 

 in Central Asia, in Japan, in California, and even our own Live 

 Oak with its Mexican relatives, may probably enough be regarded 

 as early offshoots from the same stock with Q. Ilex. 



In brief, not to continue these abstracts and remarks, and 

 without reference to Darwin^s particular theory (which DeCan- 

 dolle at the close very fairly considers), if existing species, or 

 many of them, are as ancient as they are now generally thought 

 to be, and were subject to the physical and geographical changes 

 (among them the coming and the going of the Glacial epoch) 

 which this antiquity implies — if in former times they were 

 as liable to variation as they now are — and if the individuals of 

 the same species may claim a common local origin, then we can- 

 not wonder that " the theory of a succession of forms by devia- 

 tions from anterior forms " should be regarded as " the most 

 natural hypothesis,'^ nor at the general advance made towards 

 its acceptance in some form or other. 



The question being, not how plants and animals originated, 

 but how came the existing animals and plants to be just where 

 they are and what they are, it is plain that naturalists interested 

 in such inquiries are mostly looking for the answer in one direc- 

 tion. The general drift of opinion, or at least of expectation, is 

 exemplified by this essay of DeCandolle; and the set and force 



