278 THEORY of the EARTH. 



that, through all this fpace, there are interfperfed immenfe 

 quantities of whinftone ; a body which is to be diftinguiflied 

 as very different from lava ; and now the difpofition of this 

 whinftone is to be confidered. 



SOMETIMES it is found in an irregular mafs or mountain, as 



Mr CRONSTEDT has properly obferved ; but he has alfo faid, 



that this is not the cafe in general. His words are : " It is 



' oftener found in form of veins in mountains of another 



' kind, running commonly in a ferpentine manner, contrary 



" or acrofs to the direction of the rock itfelf." 



THE origin of this form, in which the trap or whinftone ap- 

 pears, is moft evident to infpeclion, when we confider that this 

 folid body had been in a fluid ftate, and introduced, in that 

 ftate, among ftrata which preferved their proper form. The 

 ftrata appear to have been broken, and the two correfpondent 

 parts of thofe ftrata are feparated to admit the flowing mafs of 

 whinftone. 



A FINE example of this kind may be feen upon the fouth 

 fide of the Earn, on the road to Grief. It is twenty-four yards 

 wide, ftands perpendicular, and appears many feet above the 

 furface of the ground. It runs from that eaftward, and would 

 feem to be the fame with that which crofles the river Tay, in 

 forming Campfy-lin above Stanley, as a lefler one of the fame 

 kind does below it. I have feen it at Lednoc upon the Am- 

 mon, where it forms a cafcade in that river, about five or fix 

 miles weft of Campfy-lin. It appears to run from the Tay 

 eaft through Strathmore, fo that it may be confidered as having 

 been traced for twenty or thirty miles, and weftwards to Drum- 

 mond caftle, perhaps much farther. 



Two fmall veins of the fame kind, only two or three feet 

 wide, may be feen in the bed of the Water of Leith, traverfing 

 the horizontal ftrata, the one is above St BERNARD'S well, the 

 other immediately below it. But, more particularly, in the 

 ihire of Ayr, to the north of Irvine, there are to be feen upon 



the 



