54 The American Geologist. juiy, i89i 
Tertiary and Posi-Tcrtiary changes of the Atlantic arid Pacific coasts ; 
irith a note on tlic iiiutiad relations of land-elevation and ice-accuinulatio7i 
durinij the Quartenutry period. By Joseph Le Coxte. Bulletin of the 
Geological Society of America, Vol. ii., pp. 323-330, with one figure ; 
March 16, 1891. The submarine continuations of the channels of the 
St. Lawrence, Hudson, Deleware, Susquehanna, and Mississippi rivers 
are cited as proof that the Atlantic coast of North America was up- 
lifted during the Pliocene period, attaining, probably in the early part 
of the Quarternary, an altitude of 2,000 to 3,000 feet above its present 
hight. Its northern coasts were also uplifted, as shown by fiords. 
The elevation of British Columbia, according to Dr. G. M. Dawson, was 
at least 900 feet. That it may have greatly exceeded this amount, is in- 
dicated by the submerged channels discovered on the coast of California 
by Prof. George Davidson of the U. S. Coast Survey. Not less than 
twenty of these sunken fiords have been found between Cape Mendocino 
and San Diego, within a distance of about 700 miles, some of them 
reaching depths of 2,000 to 2,500 feet. Like the Hudson submarine 
channel and fiord, these have all the distinctive features of subaerial 
erosion, and they are regarded by Prof. Le Conte as decisive evidence 
that this part of the continental plateau has been greatly uplifted, sim- 
ilarly with Its eastern portion and probably at the same time. The 
submarine channels of California, however, are not continuations of the 
present rivers, and none exist opposite to San Francisco and the Golden 
Gate. Professor Le Conte therefore suggests that the drainage of the 
great valley of California during Pliocene time probably passed into the 
sea farther south by a deeply submerged channel which is traced by 
oundings in the Monterey bay. Orogenic movements, accompanying 
the Quaternary subsidence of the coast, have turned this outlet through 
the Golden Gate. Others of these submerged channels seem to have 
been canons formed by short streams in their descent from the western 
slope of the Coast Range when it was raised with the whole region far 
higher than now. 
In a supplementary note, the author concludes that the Pliocene eleva- 
tion of the continent culminated in the early Quaternary, and was one 
of the causes of the ice-accumulation ; that the load of ice caused sub- 
sidence below the present level ; that the removal of the ice was the 
cause of the re-elevation to the present condition ; out that all these 
effects lagged far behind their causes. 
Composition of certain Mesozoic igneous rocks of Virginia. By H. D. 
Campbell and W. G. Brown. Bulletin, G. S. A., vol. ii., pp. 339-348; 
March 18, 1891. Two exceptional varieties of the otherwise remarka- 
bly uniform eruptive rocks occurring in the Mesozoic belt of our Atlan- 
tic border are described, with analyses, under the names hypersthene- 
diabase and olivine-hypersthene-diabase. The former is known at lo- 
calities in Virginia, Now Jersey, and Pennsylvania; but the latter has 
been noticed at only one locality, near Rapidan, Culpeper county, Va. 
The Cinnabar and Bozeman coal fields of Montana. By Walter 
Harvev Weed. Bulletin. G. S. A., vol. ii., pp. 349-364. with a plate 
