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IN THE FAROE ISLANDS. 225 



genus of rock will be established beyond a doubt. The discove- 

 ry of submarine lavas, the idea of which first struck the cele- 

 brated Dolomieu, serves as an additional illustration of the 

 magnitude and various exertion of that power, which, when 

 subjected to the control first conceived by the ingenious 

 Hutton, explains almost every phenomenon of the mineral re- 

 gions. 



While the great point, the action of heat in the formation of 

 trap rocks, seems to be demonstrated, forming a theory of the 

 manner in which heat has operated in particular cases, is, in a 

 general view, perhaps not absolutely necessary in the present 

 state of geology. Yet it is satisfactory to the mind when any 

 explanation, consistent with the laws of nature, is suggested. 

 The theory of submarine volcanoes is not meant to be extended 

 to the appearance of beds of trap interspersed between strata of 

 sandstone and other rocks. These have been thrust among 

 the strata from below, and have probably been the cause of the * 

 strata being elevated above the sea, in which they were form- 

 ed. The succession of beds of trap, one above another, is the 

 fact which the theory of submarine volcanoes is intended to 

 explain ; and though it may not be thought to afford grounds 

 for conviction, yet, in a case where the agent employed is of 

 unlimited power, the imagination is led, by this theory, into a 

 scene on which it can dwell with some degree of satisfaction. 

 Some affect to view geological theory in the light of idle spe- 

 culation ; while others, of whom I am one, consider it the 

 main spring of research, and the direct road to discovery. 

 There are three descriptions of geological facts of importance 

 to theory • those which support it, those which are difficult to 

 account for, and those which can be explained by the opera- 

 tion of agents opposite in their nature, as fire and water. In 

 proportion as the first accumulate, the second present fewer 



Vol. VII, F f obstacles ; 



