MEMBERS OF THE PYROCRYSTALLINE ROCKS. 
71 
lachian range. This range is flanked on all sides with the 
oldest sedimentary rocks. In the British provinces, Nova 
Scotia and New Brunswick, granites resembling those of Maine 
are well known. They range, with some intermission, from 
Canso to Halifax, bordering a low rocky coast. 
§ 58. Granites of Oregon and California. Granite of several 
kinds is a constituent part of the great mountain ranges of Oregon 
and California. It is associated with traps, basalts, sienites, 
and mica and talcose slates.* According to Dr. Pickering, 
granite forms a part of the Cascade mountains, having met 
with it about twenty miles north of mount Rainier. The sum¬ 
mit of the pass of this range is however trachyte. North of 
Okanagan, and east of fort Colville, granite is the prevailing 
rock. But it occupies, according to Dr. P., an anomalous 
position, the summit of the range being formed of basalt or 
trap, while the sides only are granitic. Farther south, accord¬ 
ing to Professor Dana, or between Oregon and San Francisco, 
albitic granite is a common rock of the principal ranges, 
especially of the Shasty mountains. This is sometimes porphy- 
ritic. The color of the granite is usually light, and fine 
grained, constituting a firm mass, and little subject to decom¬ 
position; though when changed it is as white as chalk. Some¬ 
times the albite is red. The rock is barren of minerals. The 
Rocky Mountain range has its share of granite in its composi¬ 
tion, though sedimentary rocks reach the principal passes of 
the chain on the eastern slope. 
§ 59. Granites of lake Superior. The northern side of 
lakes Superior and Huron, together with the highlands of 
Wisconsin and Michigan, and between the Upper Mississippi 
and Michigan and Superior, is another extensive field of eruptive 
rocks, among which granitic and sienitic protrusions are very 
numerous. It is a region covered with drift, and hence no 
small parts of the rocks are hidden from view. 
* Dana’s Report TJ. S. Exploring Expedition. 
