PETROGRAPHIC GEOLOGY AND DESCRIPTIONS. 707 



Marble. Conglomerate.] 



Mic. This rock does not differ from No. 1367(r/) essentially. The feldspar is 

 in form of spindle-shaped, often radiating microliths, whose lamell* are frequently 

 separated by a narrow, rod-like amphibole. Yet in the main the feldspars run 

 rigidly amongst the fibres of the amphibole, the latter frequently having the pahnated 

 form mentioned under No. 1367. The spindle-shaped microliths of feldspar look 

 quite fresh compared to a few larger albite-twinned feldspars which are scattered 

 throughout the slide. One section. 



Age. Archean (Keewatin). N. H. w. 



No. 1369. MARBLE. 



Just east of Ogishke Muncie lake, near the centre of N. 1 . ; sec. 24, T. 65-6 W. 

 Ref. Annual Report, xvi, pages 95, 1-2',',. 







Mi'!/. A fine-grained, siliceous, pinkish and greenish marble, similar to No. 

 1371. No section. 



Age. Archean (Keewatin). u. s. a. 



No. 1371. MARBLE. 



Northeast end of Ogishke Muncie lake, sec. 24, T. 65-6. From the hill of greenstone where the marble 

 bi'fomes involved in the greenstone conglomerate. Compare Nos. 746, 760, 1378 and 1681. 

 Ref. Annual Report, xvi, pages 96, 123 ; Annual Report, xvii, pages 199, 205. 



Meg. Light colored, dense, irregularly faintly striped with impurities, and 

 considerably separated by short joint-planes and seams. 



Mic. While the rock is composed of cdlci-te, there are small spaces which are 

 nearly isotropic, and in these there are also small isolated and attached crystals of 

 calcite that are idiomorphic. In this isotropic substance are also a few needle-like, 

 bright blades, which, having parallel extinction, appear to be Muscovite or microliths 

 of some feldspar, as well as a few other transparent crystalline grains which cannot 

 be distinguished from feldspar, but whose nature cannot be determined. One section. 



Age. Archean (Keewatin). 



Ri'iintrk. This marble is supposed to be a product of segregation from the 

 alteration of the feldspars in the adjoining greenstone. N. H. w. 



No. 1372. CONGLOMERATE. (Greenstone.) 



Sec. 24, T. 65-6, shore of Ogishke Muncie lake. 

 Kff. Annual Report, xvi, pages 96, 98, 123. 



Meg. Greenstone, appearing conglomeratic. 



Mic. The rock is plainly a fragmental one, but <-<ilcite is the most conspicuous 

 and most abundant single mineral. It is disseminated widely, and almost every where, 

 even in the pebbles, in minute particles. With the calcite is a considerable amount 

 of fresh fi'/i/^/t/n- in form of microlitic crystals. These lie in the calcite in an ophitic 

 manner. These seem to be simple crystals. Although two or three are sometimes 



