Basalt. Diabase. Graphic granite.] 

 Quartzyte. 



PETROGRAPHIC GEOLOGY AND DESCRIPTIONS. 805 



No. 1889. BASALT. 



At the Temperance river outlet of Brule lake.* 

 Ref. Annual Report, xxii, page 12. 



Meg. A dark, heavy, fine-grained rock, with pseudamygdaloidal spots. 



Mic. The dark-greenish spots are occupied by the well-known "chloritic 

 substance," mingled with which is more or less of magnetite, calcite, epidote, sphene; 

 epidote sometimes constituting the largest part. One section. 



Age. Cabotian. N. H. w. 



No. 1890. DIABASK. 



Same place as No. 1889. Cut by veins of red granite. 

 Ref. Annual Report, xxii, page 12. 



Meg. A rather fine-grained diabase, with a little pinkish feldspar. No section. 

 Age. Cabotian. u. s. G. 



No. 1891. GRAPHIC GRANITE. 



At the spur of the Port Arthur, Duluth and Western railroad, near the camp of the Gunflint Iron mine 

 at the cut near Cross river ; S. W. % S. E. J4 sec. 27, T. 65-4 W. 

 Ref. Annual Report, xxii, page 12. 



Meg. Forms veins and patches in the gabbro. 



Mic. The large crystals of quartz and of an altered feldspar form a coarse 

 pegmatyte. The feldspar is an acid plagioclase. Illustrated by plate V, figure 2. 

 One section. 



Age. Cabotian. N. H. w. 



No. 1892. DIABASE. 



From an eigh teen-inch dike cutting the gabbro on the railroad ; S. E. ^ N. W. % sec - 27, T. 65-4 W. 

 Ref. Annual Report, xxii, page 12. 



Meg. The specimen shows nearly half the width of the dike. The rock is a 

 black, dense diabase, which at the edge of the dike is very fine grained, almost glassy. 

 No section. 



Age. Cabotian. u. s. G. 



No. 1895. QUARTZYTE. ( Garnetiferaus. ) 



At the Gunflint iron mine (Paulson's camp). 

 Ref. Annual Report, xxii, page 12. 



Meg. Cinnamon-colored mineral, is connected with the pyrite. 



Mic. The section consists of granular quartz and garnet, the former being a part 

 of the well-known iron-bearing quartzyte (Pewabic) underlying the gabbro, and the 

 latter an accidental accompaniment. There are secondary minerals, but the garnet 

 surrounds the quartz, and composes nearly one-half of the slide. It is also fresh, 



*Brul6 lake has an outlet at each end, one passing to Brul river and one to Temperance river. At the time of our visit, in 

 midsummer, they were both flowing. Compare American Geologist, xix, pp. 407-411, 1897. 



