128 THE DOCTRINE OF DESCENT. 



theory makes its way affords the best evidence that it 

 took shape and was proclaimed at the proper moment. 



That the doctrine of Descent was likewise no utterly 

 startling apparition, even though it leapt forth from the 

 head of Darwin, its greatest representative, like an armed 

 Minerva — of this we have cited at least a few of the many 

 vouchers. That its time had come, — that it was indeed 

 more than time, unless the science of the nature of life, 

 and Biology in general, was to be unduly backward, — 

 is shown by the development of Geology, which thirty 

 years prior to Darwin, after many favourable forecasts, 

 struck upon the right road to the knowledge of causes. 

 The doctrine of the formation and evolution of the 

 earth, especially in its earlier phases, during which Life, 

 in the sense generally attached to the word, originated 

 and became permanent on our Planet, — this science of 

 Geology is intimately allied with our important theme. 

 Modern Geology, especially as connected with the name 

 of Charles Lyell, must sooner or later have necessitated 

 an analogous treatment of vegetal and animal lore, and 

 we can only wonder that the crisis was so long delayed. 

 The exposition of the doctrine of Descent must, there- 

 fore, be introduced and initiated by a reference, however 

 brief, to modern Geology. 



The first edition of Lyell's *' Principles of Geology " 

 appeared in 1 830. The tenth, published in i S66, gave him 

 an opportunity of professing his full adhesion to the 

 Darwinian doctrines, to the development of which he 

 had given so great an impulse. Since 1872, the eleventh 

 edition of this masterpiece has been before the world. 

 It treats of the investigation of the lasting effects of 

 causes now in operation, as data from which inferences 



