THE LAWS OF GEOLOGICAL ACTION. 3 



profound and perhaps inscrutable problems which lie at the 

 bottom of human existence, men have in all ages invented 

 theories to explain the common phenomena of the material uni- 

 verse ; and most of these theories, however varied in their de- 

 tails, turn out on examination to have a common root, and to 

 be based on the same elements. Modern geology has its own 

 theories on the same subject, and it will be well to glance for 

 a moment at the principles underlying the old and the new 

 views. 



It has been maintained, as a metaphysical hypothesis, that 

 there exists in the mind of man an inherent principle, in virtue 

 of which he believes and expects that what has been, will be ; 

 and that the course of nature will be a continuous and unin- 

 terrupted one. So far, however, from any such belief existing 

 as a necessary consequence of the constitution of the human 

 mind, the real fact seems to be that the contrary belief has 

 been almost universally prevalent. In all old religions, and in 

 the philosophical systems of almost all ancient nations, the order 

 of the universe has been regarded as distinctly unstable, mu- 

 table, and temporary. A beginning and an end have always 

 been assumed, and the course, of terrestrial events between these 

 two indefinite points has been regarded as liable to constant 

 interruption by revolutions and catastrophes of different kinds, 

 in many cases emanating from supernatural sources. Few of 

 the more ancient theological creeds, and still fewer of the 

 ancient philosophies, attained body and shape without contain- 

 ing, in some form or other, the belief in the existence of peri- 

 odical convulsions, and of alternating cycles of destruction and 

 repair. 



That geology, in its early infancy, should have become im- 

 bued with the spirit of this belief, is no more than might have 

 been expected ; and hence arose the at one time powerful and 

 generally-accepted doctrine of " Catastrophism." That the suc- 

 cession of phenomena upon the globe, whereby the earth's crust 

 had assumed the configuration and composition which we find 

 it to possess, had been a discontinuous and broken succession, 

 was the almost inevitable conclusion of the older geologists. 

 Everywhere in their study of the rocks they met with appar- 

 ently impassable gaps, and breaches of continuity that could 

 not be bridged over. Everywhere they found themselves con- 

 ducted abruptly from one system of deposits to others totally 

 different in mineral character or in stratigraphical position. 

 Everywhere they discovered that well-marked and easily recog- 



