52 



WILLIAM J. MILLER 



an inclusion of the gabbro in the pegmatite, lack of magmatic 

 flow-structure foliation in the gabbro near the pegmatite, and 

 perfect gradation from one facies of the pegmatite into another. 

 Along the northwestern side of the same gabbro stock there 

 are several small pegmatite masses, one with fairly sharp contacts 

 and the other without. Also a number of rather rounded masses 

 of basic pegmatite (chiefly plagioclase and hornblende) from one 

 to several feet across appear to be inclusions, with fairly sharp 

 contacts, in foliated gabbro. Such pegmatite must have formed 



Fig. 8. — Sketch showing several facies of pegmatite in the gabbro at the western 

 edge of the stock on the hill one mile south-southeast of the Glen in the North Creek 

 quadrangle. 



while the gabbro was still molten. A few rods farther north a 

 small dike of acidic pegmatite with rather sharp contacts has an 

 aplitic offshoot three inches wide which bears off abruptly for 

 twelve feet into non-foliated gabbro, with fairly sharp contacts 

 against the latter. 



On the southern side of the small stock one and one-fourth 

 miles north of the Glen several moderately coarse acidic pegmatite 

 masses from three to twelve feet long lie in the gabbro, with fluxion 

 structure of the latter parallel to the borders of the pegmatite, 

 but only close to them. Contacts against the gabbro are rather 

 sharp. Well within the stock several small inclusions of the 

 country rock (granite) also lie in the gabbro parallel to a magmatic 



