PETROGRAPHIC GEOLOGY AND DESCRIPTIONS. 399 



Granite.] 



occurrence of faults, such as that at Baptism river, and eastward from there, it is 

 obviously impossible to speak at present with certainty of the stratigraphic sequence 

 of the strata of the coast. N. H. w. 



No. 526. GRANITE. ( GranopJiyric .) 



From the knob of red rock at the west side of Beaver bay (see No. 124). 



Ref. Annual Report, ix, page 32; Annual Report, x, pages 40, 41; Final Report, vol. i, page 196. 



Meg. An even-grained rock of a purplish gray color, not coarse. 



Mic. The section shows a semi-crystalline rock, i. e., one that retains still a 

 trace of its original magmatic condition. While it shows much quartz, this quartz 

 is not in definite and separate crystalline grains. Some of it is poikilitic, embracing 

 a multitude of minute impurities, many of them opaque, and some of it is pegmatitic. 

 The poikilitic parts are not clearly and fully oriented into separate areas, as is 

 frequently seen in some of the aporhyolytes, but they seem to be more interlocked 

 and blurred, as if there were still some glassy residuum. Other quartzes are evidently 

 from the original magma, having taken their form while still the fluid condition 

 remained, since they have embayments in which an isotropic glassy (?) substance is 

 seen. This glassy substance is somewhat reddened by hematite, when viewed in natural 

 light, and cannot be distinguished from the bulk of the apobsidian which constitutes 

 a prominent feature of this part of the coast. From these embayments the same 

 substance can be traced, with greater or less distinctness, throughout the slide, 

 sometimes less isotropic and frequently embracing polarizing microliths. 



There is another feature that allies this rock with No. 520, viz.: the existence of 

 clear globular feldspars which are grouped sometimes to the number of half a dozen, 

 surrounded by the same amorphous reddened substance, all extinguishing at the same 

 instant. In this case the feldspar grains are plainly of some plagiodase, since 

 occasional striation is apparent. 



All the minerals, except the porphyritic quartzes, are much clouded by fine 

 microliths and reddened by hematite, and the quartzes themselves are not free from 

 dark particles even those which might perhaps be considered to date from the 

 quartz-porphyry stage of the rock. 



The specific determination of the feldspar is impossible. While the larger part 

 of it is probably of orthodase, some is still plagioclase. 



Some magnetite and a trace of some ferro-magnesian mineral can also be 

 observed. Two sections. 



Age. Cabotian. 



Remark. This interesting rock affords another petrographic link between the 

 extremes of the red rock of the region ; i. e., between the rhyolyte and the red granite. 

 It has commonly been known as a granite, but it is more nearly a granophyre. 



