436 A SHORT HISTORY OF SCIENCE 



ture of Great Britain, he returns with more exalted conceptions of 

 the antiquity of some of our modern deposits, than he before enter- 

 tained of the oldest of the British series. 



We cannot reflect on the concessions thus extorted from us, in 

 regard to the duration of past time, without foreseeing that the period 

 may arrive when part of the Huttonian theory will be combated on 

 the ground of its departing too far from the assumption of uniformity 

 in the order of nature. On a closer investigation of extinct volcanos, 

 we find proofs that they broke out at successive eras, and that the 

 eruptions of one group were often concluded long before others had 

 commenced their activity. Some were burning when one class of 

 organic beings were in existence, others came into action when dif- 

 ferent races of animals and plants existed, it follows, therefore, 

 that the convulsions caused by subterranean movements, which are 

 merely another portion of the volcanic phenomena, occurred also 

 in succession, and their efforts must be divided into separate sums, 

 and assigned to separate periods of time ; and this is not all : when 

 we examine the volcanic products, whether they be lavas which flowed 

 out under water or upon dry land, we find that intervals of time, 

 often of great length; intervened between their formation, and that 

 the effects of one eruption were not greater in amount than that 

 which now results during ordinary volcanic convulsions. The ac- 

 companying or preceding earthquakes, therefore, may be considered 

 to have been also successive, and to have been in like manner inter- 

 rupted by intervals of time, and not to have exceeded in violence 

 those now experienced in the ordinary course of nature. 



Already, therefore, may we regard the doctrine of the sudden eleva- 

 tion of whole continents by paroxysmal eruptions as invalidated ; and 

 there was the greatest inconsistency in the adoption of such a tenet 

 by the Huttonians, who were anxious to reconcile former changes to 

 the present economy of the world. It was contrary to analogy to 

 suppose that Nature had been at any former epoch parsimonious of 

 time and prodigal of violence to imagine that one district was not 

 at rest while another was convulsed that the disturbing forces were 

 not kept under subjection, so as never to carry simultaneous havoc 

 and desolation over the whole earth, or even over one great region. 

 If it could have been shown, that a certain combination of circum- 

 stances would at some future period produce a crisis in the subter- 

 ranean action, we should certainly have had no right to oppose our 



