Orystalline Rocks of the Northwestern States. 29 
microscopic characters of this granite, prepared, after the study 
a number of thin sections, by Mr. Vanhise. 
‘These rocks are all very much alike in their chief charac- 
, arently primary are the large integral 
grains filling interstices between the other ingredients; but in 
found, not only with a single core of diallage to each crystal, 
ut with several or many spots of the original mineral. 
*Geol, of Wis., iv, p. 662. 
+G. W. Hawes has described and figured a similar relation between augite and 
ge hornblende, in the Lithology of New Hampshire, pp. 57, 206; and Plate 
