479 



how ic efcaped the general difintegration of all the rocks of that 

 world ; and how, in its prefent unwieldy mafies, it travelled from 

 the old world to the mw, without undergoing the procefs of commi- 

 nution, an operation by the foregoing theory, indifpenfably necefla- 

 ry to enable it to perform the journey. 



As to the ftratification of whynn-Jlone, or bafalt, Mr. Playfair is 

 pofitive. He fays (fection 76) " to conceive aright the origin of that 

 " clafs of unftratified rocks, diftinguiftied by the name of whynn- 

 " flone;" — and again, fame fedion, " thefe unftratified rocks;" — alfo, 

 (feftion 61) " Whynn, though not ftratified." 



Mr. Playfair (fedlion 29) confiders it as a good defect in Buffon's 

 Theory, " That it makes no diflinction between ftratified and unftra- 

 " tified bodies ;"— " this fyftem, therefore, has but a very diftant 

 " refemblance to the Hutlonian Theory;" — and again (feclion 125) 

 " Buffen has no means of explaining the unftratified rocks." 



From this laft paffage it is obvious, that Mr. Playfair confiders the 

 want of ftratification in the rocks he mentions, as indifpenfably ne- 

 cefiary to Dr. Huttoii's, Theory. 



It is now full time to cotnc to facls ; I muft, therefore ftate, that nature 

 feems to rae to have arranged bafalt, that is, ivhynjione, in more regular 

 ftrata than any other fubftance whatfoever ; to confirm this, I muft requefl 

 the reader to turn back to a paffage in this memoir, in which I gave a mi- 

 nute account of the ftrata of our bafaltic country, in a courfe of thirty miles, 

 nineteen parts of which out of twenty, are accumulations of bafalt ftrata, 

 arranged with confummate regularity. 



Wherever we find the lame material, nature has difpofed it m the 

 fame manner ; thus, if we proceed fouthward from MagiWgan rock, hj 

 the bafaltic mountains of Bien Braddock and Carntogher, to the point 

 where the bafalt terminates in the abrupt faces of Monynceny, hanging over 

 the valley of the Mayola ; we find the bafe of all thefe mountains a 

 mighty ftratum of Vr-hite limeftone, upon which fucceffive bafalt ftrata are 

 _ heaped upon one another quite up to their fummits : the regular ftrati- 

 fication of this mafs is occafionaliy difclofed, whenever abrupt precipices 



occur,. 



