112 NEW YORK STATE MUSEUM 



material, which has evidently been produced at their expense. 

 The feldspars occasionally show the same thing. It is however 

 in no sense a cataclastic structure, as the grains are not mere 

 shattered fragments of the larger crystals but consist of all the 

 minerals mentioned above. The process is one of recrystalliza- 

 tion and wholly owing to the metamorphism. In these granular 

 mixtures the augite, hypersthene and labradorite differ from- the 

 primary minerals in being wholly free from the inclusions with 

 which they are packed. 



In the main, recrystallization has commenced at the contacts 

 between the feldspar and augite, or feldspar and magnetite, and 

 such minerals as garnet which were not in the original rock have 

 resulted from the incorporation of material from each of the ad- 

 joining minerals. In several slides garnets of quite large size, 

 fully as large as any in the slide, are found as inclusions in the 

 primary feldspars, and at times augite and hypersthene are found 

 with them. In an unmetamorphosed rock their occurrence in 

 such situation would be proof of their primary origin, as they 

 must have been formed before the feldspar in order to be so in- 

 cluded; but that can hardly be the case here, and the writer is 

 disposed to account for them in the same way as before, the augite 

 or magnetite necessary for their formation perhaps being fur- 

 nished by the inclusions of these minerals with which the feld- 

 spar is so heavily stocked. Often a narrow zone of the feldspar 

 around these included garnets has been completely freed from 

 these inclusions, which is corroborative evidence of the truth of 

 this explanation so far as it goes. It does not help to explain 

 why such inclusions of garnet are not more often met with, the 

 small ones being always present, but the same difficulty will apply 

 in a less degree to the entire rock, as garnet is by no means found 

 along all the contacts between the minerals concerned. Undoubt- 

 edly percolating water played a large part in the process, and the 

 garnet inclusions in the feldspars are always on the line of cleav- 

 age cracks. 



Two different varieties of hornblende occur in these rocks, 

 though never together so far as the writer's experience goes. 



