405 



which is a granular mixture of hornblende and 

 lamellar feldspar. It is what is vaguely called 

 primitive grunstein. In it we can recognize 

 traces of quartz and pyrites. Submarine rocks 

 probably exist near the coast, which furnish 

 these very hard masses. I have compared 

 them in my journal to the paterlestein of Fich- 

 telberg, in Franconia, which is also a diabase, 

 but so fusible, that glass buttons are made of 

 it, which are employed for the slave-trade on 

 the coast of Guinea. I believed at first, ac- 

 cording to the analogy of the phenomena which 

 the mountains of Franconia furnish *, that the 

 presence of these hornblende masses with crys 

 tals of common (uncompact) feldspar indicated 

 the proximity of transition rocks ; but in the 

 high valley of Caraccas, near Antimano, balls 

 of the same diabase fill a vein crossing the mica- 

 slate. On the western declivity of the hill of 

 Cape Blanco, the gneiss is covered with a for- 

 mation of sandstone, or agglomerate, extremely 

 recent. This sandstone combines angular frag- 

 ments of gneiss, quartz, and chlorit, magnetical 

 sand, madrepores, and petrified bivalve shells. 

 Is this formation of the same date as that of 

 Punta Araya and Cumana ? I sent numerous 

 specimens of it to the cabinet of the King of 

 Spain at Madrid. 



* Near Schauenstein, and Steben, where the carburetted 

 transition schist predominates. 



