i(> Mechanical deposits in mountains, &c. 



between each have, however, a feries from the mod complete granular quarts 

 are gradual. to ^ )(i mQ ^ p er f e( c^ m j ca fl ate# Again, mica flate, which dif- 



^o'm fl neTfs d ^ rSfersfrom S neI{ ^ in wanting felfpar, is to be obferved in all 

 wanting felfpar; the intermediate ftages until it paHes into complete gneifs j 

 but here alfo the t j ie g^jf^ vvhieh is principally diftinguimed from granite by 

 equally gradual, its flaty fracture, gradually lofes this fracture, and at length is 



And gneifs dif- no t to De diilinguifhed from granite. Thus we have a coni- 

 fers from granite , , . ° A ■ . . , 

 by its flaty fiac- plete gradation from the pureft granular quartz to granite, and 



ture, which it not only in hand fpecimens, but in the mountains themfelves. 



toffs* U y ^ tncre ^ ore follows, that if granular quartz is a mechanical 



The gradation depofit, fo is granite, a pofition which I believe the Hutto- 



being perfect, That the granular quartz fliould occur fometimes of a very 



the one is no j 00 f e texture; nay, even as Profeflbr Playfair remarks fandy, 



more a mecha- # ... . r . ., 



nical depofit is not furprizing, for in granite and bafalt we have iimilar ap- 



than the other. p eara nces. Even in veins, which to ufe Profeflbr Playfair's 



no proof of me- own words, bear all the marks of complete fufion, layers of 



chanical depofi- granular quartz, from the mod: compact to the loofenefs of fand 



and brers of have been obferved. The great fand veins in the Hartz af- 



fand are found ford remarkable inftances of this ; alfo, as I have more lately 



in th^vokanic difcovered, the lead veins at Wanlock-head in Lancafhire. 



theory are faid 



to bear every Account of Organic remains zvhich have been difcovered in the 



mark of com- 77t .,^. f^ Trapp formation. 



plete fufion. * ■ ■ 



General obfer- Many different accounts had been given of the geognofiic 



relations of the rocks of this formation, before they engaged 

 the attention of Werner, the great founder of true geognnfia. 

 After having made the remarkable difcovery upon the hill of 

 Scheibenberg, he extended his inquiries to all the bafalt hills 

 in Germany, and found in every quarter correfponding ap- 

 pearances. This confirmed more completely the conclufions 

 he had then drawn, and intirely overthrew the volcanic fy{- 

 tem. He however did not Hop here ; his after obfervations 

 difelofed a conne&ion among thefe appearances, which at firft 

 he was not probably aware of; they placed the Neptunian 

 fyftera beyond the reach of attack, and completely annihilated 

 a hoft of hypothefes. He proved, 

 Refuks. i. That 1. That this is the neweft of all the great rock formations, 

 this is the new- f which the crufi of the earth is computed, 

 rocks.^ £reat 2 ' Tnat a11 the a PP arent ty unconne&ed hills and manes of 

 a. That all the this formation, have formerly flood in connexion with each 

 U©w unconnec- Qtrier> 



3. That 



