PETEOGRAPHIC GEOLOGY AND DESCRIPTIONS. 179 



Diabase. Amygdaloid.] 



No. 111A. DIABASE. (Fine.) 



West side of little bay in sec. 7, T. 54-8 W.; from a small island. 

 Ref. Annual Report, ix, page 29; Annual Report, x, page 39. 



A very fine-grained, heavy, dark gray rock, whose component minerals 

 cannot be distinguished megascopically. The rock contains.a few small (not exceed- 

 ing one-eighth of an inch in diameter) amygdaloid-like cavities now filled, or only 

 lined, with minute quartz crystals. 



Mi<'. This rock in structure and composition, except that it lacks the chloritic 

 amygdules, is quite similar to No. 98. 



One section. 



Age. Cabotian. 



Remark. Directly overlies rock No. 110, and probably belongs immediately 

 above the rock of the bluff at the mouth of Gooseberry river. u. s. G. 



No. 11 IB. AMYGDALOID. (Decayed.) 



West side of little bay in sec. 7, T. 54-8 W. From another small island. 

 Ref. Annual Report, ix, page 29; Annual Report, x, page 39. 



Meg. The rock is yellowish green in color, is earthy and very much decayed, 

 and contains green areas of chlorite (?) apparently filling amygdules. The rock 

 appears to be a much decayed, basic amygdaloid. 

 No section. 



Ai/f. Cabotian. u. s. G. 



No. 112. DIABASE. 



Splitrock point; holds masses of No. 113 (anorthosyte). 



Ref. Annual Report, ix, pages 29, 30; Annual Report, x, pages 40, 139; American Association for the 

 Advancement of Science, vol. xxx, page 162. 



M<'(j. A dark gray, compact, very fine-grained diabasic rock. 



Mir. The section is made up of long lath-shaped plagioclases, showing more or 

 less flow structure by their arrangement. These plagioclases are imbedded in a 

 groundmass composed of large plates of augite, greenish alteration material, and an 

 opaque black substance, much of which is magnetite, but some of which may repre- 

 sent original glassy material. 



No section. 



Age. Cabotian; Beaver Bay diabase. 



Remark. In the field description of this rock, No. 524 is referred to. No. 

 524 is a good example of an olivine diabase, and it is considerably coarser grained 

 than No. 112. u. s. G. 



