THE EVOLUTION-HYPOTHESIS. 437 



similarly caused. Here and there are sedimentary deposits 

 now slowly taking place. At this place a shore has been 

 greatly encroached on by the sea during recorded times ; and 

 at another place an estuary has become shallower within 

 some generations. In one region an upheaval is going on at 

 the rate of a few feet in a century; while in another region 

 occasional earthquakes- cause slight variations of level. Ap- 

 preciable amounts of denudation by water are visible in some 

 localities; and in other localities glaciers are detected in the 

 act of grinding down the rocky surfaces over which they 

 glide. But these changes are infinitesimal compared with 

 the aggregate of changes to which the Earth's crust testifies, 

 even in its still extant systems of strata. If, then, the small 

 changes now being wrought on the Earth's crust by natural 

 agencies, yield warrant for concluding that by such agencies 

 acting through vast epochs, all the structural complexities of 

 the Earth's crust have been produced; do not the small 

 known modifications produced in races of organisms by natu- 

 ral agencies, yield warrant for concluding that by natural 

 agencies have been produced all those structural complexities 

 which we see in them ? 



The hypothesis of Evolution then, has direct support from 

 facts which, though small in amount, are of the kind required ; 

 and the ratio which these facts bear to the generalization 

 based on them, seems as great as is the ratio between facts and 

 generalization which, in another case, produces conviction. 



§ 120. Let us put ourselves for a moment in the position of 

 those who, from their experiences of human modes of actioji, 

 draw differences respecting the mode of action of that Ulti- 

 mate Power manifested to us through phenomena. We shall 

 find the supposition that each kind of organism was separately 

 designed and put together, to be much less consistent with 

 their professed conception of this Ultimate Power, than is the 

 supposition that all kinds of organisms have resulted from 

 one unbroken process. Irregularity of method is a mark of 



