PETROGRAPHIC GEOLOGY AND DESCRIPTIONS. 187 



Diabase. Anorthosyte. Granite.] 



ites are earlier than the rest of the feldspar, although no sharp line can be drawn 

 between them, and the completely allotriomorphic labradorites were the last to crys- 

 tallize. In structure this rock differs from any already described in this work. In 

 general it resembles the fine-grained gran uli tic dolerytes described by Judd from the 

 Tertiary flows of Ireland and Scotland.* u. s. G. 



I'i'iiin /!.. This is the first instance of the occurrence of such a rock in the coast 

 series. Its resemblance to the "muscovado" division of the gabbro suggests that it 

 may exist here in the form of a transported block, having been included in the great 

 sheet (Nos. 114, 115, 116, etc.) in the same manner as the blocks of anorthosyte. 

 Sufficient field notes are wanting. (See, however, No. 137.) N. H. w. 



No. 123. DIABASE (with olivine). 



From the bluff east of Castle Danger. Resembles No. 11G. 



Kef. Annual Report, ix, page 32; Annual Report, x, page 139; American Association for the Advancement 

 of Science, vol. xxx, page 162. 



Mcj. Uniform and medium grained, dark gray, having the aspect of an ordinary 

 diabase. 



Mic. The rock is composed of the usual minerals, in the usual petrographic 

 structural relations, and needs no further specification. It is a fresh rock and makes 

 a good illustrative slide. Doubtless from the same mass as No. 114, etc. 



Aye. Cabotian; Beaver Bay diabase. N. H. w. 



No. 123 A. ANORTHOSYTE. 



Block lying within No. 123. 



Ref. Annual Report, ix, page 32; Annual Report, x, page 64. 



Meg. A coarse mass of plagioclase similar to Nos. 113 and 120. 



No section. 



Age. Cabotian anorthosyte. u. s. G. 



No. 124. GRANITE. 



Bluff at Beaver Bay entrance, on the west side. Much jointed, semi-basaltic, supposed to be the equiva- 

 lent of No. 119 (see No. 526). 



Ref. Annual Report, ix, page 32; Annual Report, x, page 141; Proceedings of the American Association 

 for the Advancement of Science, vol. xxx, page 164; Bulletin viii, page xxxiii. 



Meg. A compact, fine-grained rock of a dull pinkish color. Small feldspars 

 and quartz are seen to make up most of the rock. There are also small grains and 

 needle-like forms of a black mineral. 



Mic. In ordinary light a very few, rather clear feldspar crystals are seen in a 

 cloudy, indistinct groundmass; also a few clear sub-angular quartz grains. Under 

 polarized light the groundmass breaks up into irregularly and not distinctly outlined 

 areas of feldspar intergrown with quartz to form micropegmatyte. Some of the feld- 



*J. W. JUDD : Quarterly Journal, Geology Society, vol. xlii, pp. 49-97, 1886. 



