528 General Notes. [May, 
Mt. Hood.—Hypersthene and hornblende andesites. 
Mt. Shasta.—Basalt, and hypersthene and hornblende andesites. 
Lassen’s Peak.—Basalt, hypersthene, hornblende, and quartz- 
bearing andesites (dacite or nevadite). 
The paper, from the point of view of our authors and their 
method of study, is an excellent one, and they are to be congrat- 
ulated on the results. —M. E. Wadsworth. 
continent, will make a surface expansion and contraction of 
one mile, every year. This cannot go on forever as an irresistible 
force without making some permanent changes. It may only af- 
fect the upper stratas so much, and it may be relieved by fissures 
somewhat. But in time fissures may be obstructed, either by 
minerals deposited from water, or by other means, so something 
must give way. The upper strata may be gradually compressed, 
or may slip upon those below. Elevations may slowly rise, or m- 
supportable tensions may occur, causing earthquakes, or even 
volcanic action. 
less continuous and more striking result may come from 
the emergence of large areas from the sea. The ocean one 
cially where covered by arctic currents, must be of low tempera: 
ture to a very considerable depth. Shutting out the arctic current 
would raise the temperature, and elevation from the sea w 
permanently raise it from ten to thirty degrees to a great wr 
This, however gradual, would produce an expansion which w a 
be irresistible and certainly produce great permanent chani 
as bending and elevation of strata., The bending and el d less 
might be toward one or both margins, where the cold an 
elastic sea bed gave fixed resistance to further movement. aa 
haps the lines of elevation would be at right angles to e 
of thrust across broad plains of expansion, to which ag já 
be slightly curved. Such forms are shown in many 8. AO. 
mountain systems, as if to point to the source O 
thrusts producing them. cat such systems may be tavada 
the globe in such order as to apparently indicate variou 
. . kas ; i se. 
laws and considerations affecting the action of this ges st have 
produced elevatory and other changes in all geologic 1 eas 
inexorable iron grasp, while ice and winds and waves, ~ Sam J. 
and sea have worn away. I present it for discussion. 
Wallace, Keokuk, Iowa. 
GrotocicaL Notes.—General—The Geolog! Ireland will be 
of England and Wales is now completed; that of from comf 
finished in a few years; but that of Scotland is far l o at his O78 
The work was commenced by Hy. T. De la Pane the Geolog" 
expense, and it was through his efforts and tact t 
