308 M. B. Studer on the Origin of Granite » 



and still more to the local description of those regions which 

 have become classical from their particular formations, as for 

 example, the Parisian basin for the lower tertiary, Thuringia 

 for the Zechstein group, &c., would better correspond with 

 what is desiderated, than those disquisitions which abound in 

 geological books, whose authors not being zoologists, occupy 

 themselves chiefly with descriptions of the mountain rocks, and 

 the relations of stratification, and thereby confound every thing. 

 What remains after the separation from our science of the doc- 

 trine of the earth's formation, has assumed, in our latest works, 

 more and more the aspect of physical geography, and must in- 

 deed altogether coincide with this science. To treat separate- 

 ly, of the effects of erosion, and of the doctrine of sedimentary 

 deposits, as something independent of all that is necessarily 

 associated with this subject in physical geography, is altoge- 

 ther unscientific. The eff*ects of heat and pressure in produ- 

 cing the consolidation of these deposits, and in inducing pecu- 

 liarity of structure, different coloration, and so forth, — how 

 they, by stronger influence, produced metamorphosis, or par- 

 tial fusion ; the formation of mountain-chains from these depo- 

 sits, and their elevation from the bottom of the ocean, — the 

 outpouring of the molten masses in dykes and streams — all 

 these agencies of the new theory can be satisfactorily described 

 only in accordance with the principles of general physics, and 

 arc entirely incongruous with historical-organic-geography ; 

 and, in these matters, mineralogical skill will find ample scope 

 for its due exercise. 



And now this letter, which should have been a short one, 

 has exceeded all bounds. This day four weeks, I start di- 

 rectly over Mont Cenis for Turin, whence I proceed to Ge- 

 noa, and other places. 



Bern, March 2. 1840. 



