THEORY of the EARTH. 277 



forming dry land above its furface, it will be allowed, that we 

 have difcovered the fecret operations of nature concocting fu- 

 ture land, as well as thofe by which the prefent habitable earth 

 had been produced from the bottom of the abyfs. Here, there- 

 fore, we mail at prefent reft the argument, with endeavouring 

 to fhew that fuch is actually the cafe. 



IT appears from CRONSTEDT'S Mineralogy, that the rock- 

 ftone, called trap by the Swedes, the amygdaloides and the 

 fchwarts-ftein of the Germans, are the fame with the whin- 

 flone of this country. This is alfo fully confirmed by fpeci- 

 mens from Sweden, fent me by my friend Dr GAHN. What- 

 ever, therefore, {hall be afcertained with regard to our whin- 

 ftone, may be fo far generalized or extended to the countries of 

 Norway, Sweden, and Germany. 



THE whinftone of Scotland is alfo the fame with the toad- 

 flone of Derbyfhire, which is of the amygdaloides fpecies ; it 

 is alfo the fame with the ragftone of the fouth of StafFordfhire, 

 which is a fimple whinftone, or perfect trap. England, there- 

 fore, muft be included in this great fpace of land, the mineral 

 operations of which we explore j and alfo Ireland, of which 

 the Giants Caufeway, and many others, are fufficient proof. 



IN the fouth of Scotland, there is a ridge of hills, which ex- 

 tends from the weft fide of the ifland in Galloway to the eaft 

 fide in Berwickfhire, compofed of granite, of fchiftus, and of 

 filiceous ftrata. The Grampians on the north, again, form 

 another range of mountains of the fame kind ; and between 

 thefe two great fields of broken, tumbled and diftorted ftrata, 

 there lies a field of lefTer hardnefs and confolidation, in gene- 

 ral ; but a field in which there is a great manifeftation of fubter- 

 raneous fire," and of exerted force. 



THE ftrata in this fpace confift, in general, of fandftone, 

 coal, limeftone or marble, ironftone, and marl or argillaceous 

 ftrata, with ftrata of analogous bodies, and the various compo- 

 fitions of thefe. But what is to the prefent purpofe is this, 



that, 



