574 Reports and Proceedings — American Association. 
be identical with the last, and probably at Dean Bridge. Several of 
tbe species wliicli occur low down in tkis series attain their greatest 
development in, and are ckaracteristic of, the Carboniferous Lime- 
stone series. 
II. — American Association for the Advancement of Science, 
Nasliville, Tenn., August 31, 1877. — Prof. T. Sterry Hunt read a 
paper on “ The Geology of the Older Bocks of Western America,” of 
which the following is a synopsis : — 
Prof. Sterry Hunt called attention to the great types of crystalline 
stratified Eozoic rocks which he has recognized in the eastern part 
of the continent and in Europe, and which he has endeavoured to 
show constitute distinct groups, well rnarked, both litliologically and 
geognostically. He then gave some conclusions drawn from obser- 
vations made by himself at a few points among the crystalline rocks 
during a late journey in the West. His examinations of those in 
the Bocky Mountains were made in the Sangre de Christo Bange, 
near Garland ; in the Front or Colorado Bange ; at the Ute Pass and 
Gien Eyrie ; and also along Clear Creek Canon, and about George- 
town. In all of these localities he found gneissic rocks, frequently 
granitoid, often hornblendic, but scarcely micaceons, and apparently 
identical with the Laurentian series of the East. He referred to the 
jiublished observations of the late Mr. Marvine, in Hayden’s Beport 
for 1873, who had carefully studied these rocks in the Colorado 
Bange, and who compared them to the Laurentian ; and he agreed 
with Mr. Marvine in regarding as indigenous the red granitoid rocks 
in the region of the Ute Pass. Similar granitoid rocks at and near 
Sherman, on the Union Pacific Bailroad, are also, according to 
Prof. Hunt, probably of the same nature. He referred in tliis con- 
nexion to the area of labradorite rocks having the character of the 
Norian series, found in the Bocky Mountain region, in Wyoming, but 
known to the Speaker only through specimens. 
The rocks of the Wasatck Bange, as seen in the Devil’s Gate 
on the Weber Biver, are Laurentian, to which are to be referred 
also the crystalline stratified rocks found in the same ränge further 
south, in the upper part of the Little Cottonwood Canon. Here, 
among loose blocks of the gneiss, are found occasional masses of 
coarsely crystalline limestone, with mica, and others of a peculiar 
type of pyroxenic rock, which accompanies similar limestones in the 
Laurentian series. The crystalline rocks in the lower part of the 
same Canon are, kowever, well-marked exotic or eruptive granites. 
Eruptive granites are found in California, wkere they abound 
among the foot-hills of the Sierras, in Placer and Nevada counties. 
The crystalline schists seen by the autkor in these counties, and in 
Amador county, are Huronian, and liave all the characters of the 
Huronian series, as seen in the eastern regions of North America, 
and of the pietri verdi of the Alps. To this horizon are also to be 
referred the similar crystalline rocks of the Coast Bange of California, 
as seen near San Francisco and San Jose. The auriferous veins 
which, in the Bocky Mountains, intersect the Laurentian gneisses, 
are found in the Sierras alike in the Huronian schists, and in the 
eruptive granites which probably penetrate the Huronian series. 
