vis 
. F 
G@. H. Williams—Pyroaene and Hornblende. 263 
_ which it is impossible either to adequately describe or portray. 
e hypersthene and hornblende substance, which are well 
Well as the fine lamella (marked b in the figure) of both the 
Ypersthene and hornblende are in twinning position to the 
two ends and the smaller middle portion (marked a), and all the 
part of the larger one. This exhibits in a smaller scale 
‘imits once occupied by the ersthene. There are the same 
Uregular patches of hornblende over the surface, but here, the 
