TRAl' KOCKS. H)i 



wacke, and of a puddingstonc, which sometimes contains ma- 

 rine shells, 'i'he ridge in question then, four miles east of 

 Cailisleand distant twenty-lour miles from the basalt of the 

 Conncwago Hills, stretcliesjjy a course somewhat mcandrous, 

 from the foot of the North Mountain, across the valley, till 

 it arrives at within two miles of the South Mountain, where 

 it ttrminatcs abruptly, filling the cavities of the bottom of 

 the ViilJey, and forming an overlying unconformable mass 

 of the newest flcetz trap of Werner, so unlike every other 

 rock in the neighbouriiood, as to arrest the attention of the 

 inhabitants. Its base is about three hundred yards broad, 

 and its height from twenty to thirty, its summit being nearly 

 a dead line. The transverse direction and want of con- 

 formity to the stratification of the limestone, as well as the 

 isolated situation of the ridge, give it a strong appearance 

 of having originally been a stream of lava: to convince one 

 of which, nothing is wanting but an extinguished crater in 

 the North Mountain. But I by no means consider its ab- 

 sence a decisive objection ; for rocks undoubtedly volcanic 

 are found, where all vestiges of a crater have long been ob- 

 literated. But in the present instance I see no necessity for 

 one having ever existed. If there is any position in geology 

 thoroughly established, it is that the crust of the earth has 

 undergone a series of great and sudden revolutions, which 

 have buried all the countries that were before inhabited. 

 From the animal and marine organic remains alternately 

 imbedded in the dittcrent strata of transition and secondary 

 rocks, it is demonstrated by M. Cuvier, that every part of 

 the surface of the globe has, by subsidence or upheaving, 

 alternately l)ecn the bottom of the sea and dry land. To 

 what cause i)ut subterraneous tire can effects such as these 

 be attributed ? It is idle to talk of tlie motion of the sea 

 from east to west, of the action of the tides, or deposits of 

 sediment : unless we return to the exploded notion of the 

 earth having suffered violence from the oblique stroke of 

 a comet, we shall be unable to imagine any possible force 



VOL. U. X 



