22S OS GKANITE. 



in veins in granite, alfo the brown iron ore, but this is fa? 

 Molybdena hi- fddomer than the red. Molvbdena has as yet only occurred 



therto found . . . _ \ . . / ' 



only in granite. ,n g ra mte, either lnteriperled, or in veins of the oldeft forma- 

 tion, as at Schlackenwalde, Geya, and Altenberg. 

 Bifmuth, cobalt, Bifmuth, cobalt, blende, galena, and feveral ores of cop- 

 and particularly P er nave Deen found in granite. Of all metals, however, tin 

 ^ n « h the one moft frequently found in granite, and in the great 



mining field of Cornwall, it is ohferved, that copper occurs 

 frequently in primitive flate, but the tin in granite. 



The preceding obfervations refer principally to the old gra- 

 nite, which, as far as our experience goes, is <he oldeft of all 

 the rock formations. Werner has difcovered other granite 

 formations, which are of a newer date. 

 Mure modern ] ft. Upon the Schneekoppe> the moft elevated part of the 



auernating with Riefungebirge, which is about 5000 feet above the level of 

 gneifs. the fea> granite alternates with gneifs, and hence Werner 



confiders it a diftind formation *. 

 containing flate. 2d. At Greifenftein in Upper Saxony, Werner obferved 

 granite which contained pieces of flate lying over ftrata of pri- 

 mitive flate, hence he juftly reckons it to be a diftinft forma- 

 tion, which is newer than either of the preceding. 

 Wm& of granite 3d. At Auerfberg, near Eibenftock in Saxony, and at 

 of muriate™ 13 Faftenberg near Johangeorgenftald, Werner difcovered veins 

 and primitive of granite traverfing ftrata of mica flate and primitive flate, 

 " ate * and this he is at prefent inclined to confider a new formation. 



In Scotland granite veins are very common, and feveral cir- 

 cumftances lead me to believe, that thefe and the Aueriberg 

 are the fame formation. They are probably both connected 

 Characters of with the Greifenftein formation. Werner mentions a few par- 

 the newer gra- (_j cu ] ars vvhich he confiders as chara&eriftical for the newer 



nitej ulually 



low, red, fine granite formations. 



grained, &c. j # Granite, which occurs in low filiations, may be fuf* 



peeled to belong to the Greifenftein formation. 



2. The newer granite has generally a deep red colour, is 



more frequently fine than coarfe grained, contains garnets, and 



is not porphyritic. 



* I was fo fortunate as to have the opportunity of examining 

 this formation in company with Dr. Mitchell. We obferved the 

 granite alternations three times with the gneifs* 



The 



