142 Journal of the Mitchell Society [March 



are usually layers of ma<^netite next to the actinolite, and in the mag- 

 netite are frequently small streaks of pyrite. That these various de- 

 formations produced little effect upon the structure of the carbonates 

 is due no doubt to the fact that these have recrystallized since the 

 action of the forces producing the deformations ceased. 



Here and there through the ore there is also considerable dark 

 hornblende. It occurs in large (piantity in some fragments on the 

 mine dump. It apparently is in fairly large dikes in which horn- 

 blende, magnetite and frequently garnet are intermingled. Where 

 the hornblende .is in dikes a foot or more wide their interiors are 

 coarse black hornblende free of garnet. In the smaller dikes, on the 

 other hand, the hornblende masses often enclosed small lenses of lime- 

 stone, which have been nearly completely changed to pink garnet. In 

 some instances garnet and hornblende are in equal quantities. The 

 limestone in contact with the hornblende is often banded and it fre- 

 quently contains lenses of magnetite. In contact with the hornblende- 

 garnet is a narrow layer of tine-grained hornblende, carbonates and 

 pyrite with the latter usually in very thin seams parallel to the bound- 

 ary. Beyond this are bands of carbonates and magnetite and of 

 carbonates and black mica. The banding is thus the result of con- 

 secutive layers of coarse black hornblende, aggregates of black horn- 

 blende and red garnet, aggregates of fine-grained dark and light horn- 

 blende, thin seams of pyrite and of carbonates, streaks of magnetite 

 and finally layers of carbonate and black mica. There is no common 

 elongation of the carbonate grains in the limestone, but the rock in 

 the neighborhood of the dikes has a distinct sehistosity due to the 

 parallel arrangement of the layers. 



Often near the borders of the ore deposit and occasionally within 

 its mass are also irregular aggregates of red garnet, black hornblende, 

 magnetite and carbonates in which the garnet is predominant. The 

 hornblende on the whole looks as though it were intrusive and the 

 garnet as though it were a contact product between hornblende and 

 the carbonates. These aggregates are traversed by little veins of white 

 calcite and colorless quartz and contain here and there nests of these 

 minerals, which are unquestionably secondary. 



Pyrite is not common anywhere in the ore. It occasionally occurs 

 as thin layers between the layers of granular, light green hornblende 

 and the marble, and in a few places scattered through the magnetite- 



