NOME Vm. VOLCANIC GLUTfcNITE. 50? 



marble, of yellowish marble with a fine saline 

 grain, which takes the polish ; of grey stone of 

 a very fine paste, which cannot be scratched by 

 steel, but which nevertheless effervesces briskly 

 with nitrous acid : it seems to he siUceo-calca- 

 reous. The different fragments of these stones 

 are imbedded in a grey lava, rather earthy, but 

 solid, mixed with many black pyroxenes, divided 

 into very small fragments. 



" 7. Bricia, with fragments of white and grey 

 marble, and some kernels formed of a mixture 

 of clear felspar, and a black substance which has 

 some resemblance to hornblende. Conglome- 

 rated nodules of black mica are also found in it. 

 The several foreign bodies are imbedded in a 

 grey lava, which contains in great abundance 

 small fragments of pyroxene, of a brilliant black 

 in appearance, but which, observed with a lens 

 in a strong light, are found to be green : some 

 strongly marked crystals of that substance are 

 even distinguished, which are diaphanous and 

 of a grass green, and some spangles of silvery 

 mica. 



" 8. Bricia, with large nodules of volcanic 

 chrysolite, of a greenish and yellowish oolour, 

 mixed with large fragments of porous lava, and 

 of black compact lava almost scorified, cemented 



