Hutton according to Play fair. 261 



which at the surface are easily separated, might occasion the 

 fusion of some bodies which in our fires are only calcined." 

 Hence the objections which are so strong and unanswerable, 

 when opposed to the theory of volcanic fire, as usually laid 

 down, have no force at all against Dr Hutton's theory ; and 

 hence we are to consider this theory as hardly less distinguished 

 from t!)e hypothesis of the Vulcanists, in the usual sense of that 

 appellation, than it is from that of the Neptunists, or the disci- 

 ples of Werner. 



III. The third general fact on which this tlieory is founded, 

 is, that the stratified rocks, instead of being either horizontal, 

 or nearly so, as they no doubt v/ere originally, are now found 

 possessing all degrees of elevation, and some of them even per- 

 pendicular to the horizon ; to which we must add, that those 

 strata which were once at the bottom of the sea, are now raised 

 up, many of them, several thousand feet above its surface. 

 From this, as well as from the inflexions, the breaking and 

 separation of the strata, it is inferred, that they have been raised 

 up by the action of some expansive force placed under them. 

 This force, which has burst in pieces the solid pavement on 

 which the ocean rests, and has raised up rocks from the bottom 

 of the sea into mountains 15,000 feet above its surface, exceeds 

 any which we see actually exerted, but seems to come nearer 

 to the cause of the volcano or the earthquake, than to any 

 other, of which the effects are directly observed. The immense 

 disturbance, therefore, of the strata, is in this theory ascribed 

 to heat, acting with an expansive power, and elevating those 

 rocks wliich it had before consolidated. 



IV. Among the marks of disturbance in which the mineral 

 kingdom abounds, those great breaches among rocks, which are 

 filled with materials different from the rock on either side, are 

 the most conspicuous. These are the veins, and comprehend not 

 only the metallic veins, but also those of whinstone, of porphy- 

 ry, and of granite, all of them substances more or less crystallized,' 

 and none of them containing the remains of organized bodies. 

 These are of posterior formation to the strata which they inteT- 

 scct ; and in general also they carry with them the marks of the 

 violence with which they have come into their place, and of the 

 disturbance which they have produced on the rocks already 



