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AMERICAN. NATURALIST. 
Vol. VI.— FEBRUARY, 1872.—No. 2. 
LEAHY O)OD > 
THE MOUNTAINS OF COLORADO.* 
BY J. W. FOSTER, LL.D. 
—1+o2 
TOPOGRAPHICAL Fratures.— The mountains of Colorado form, 
perhaps, the most striking feature in the orology of the United 
States. Regarding the several ranges which traverse the region 
between Mexico on the south and the British Possessions on the 
north as parts of one stupendous whole, whose upheaval in the 
main may be referred to one geological epoch, we find that along 
the fortieth parallel the most active telluric forces were exerted, 
producing the widest expansion and culminating in the loftiest 
peaks. Between the Sierra Nevada on the west and the Wasatch 
on the east, the ridges, with their intervening valleys, reach an ex- 
pansion of not less than a thousand miles. Traced north and south 
they not only diminish in height but contract in width to about — 
four hundred miles. There are five or six peaks in Western Col- 
orado which attain an altitude of over fourteen thousand feet 
above the sea, constituting the highest ground in the Uni 
States, with the exception of a region on the head waters of Kern 
River where there is a single point, Mt. Whitney, estimated at 
fifteen thousand feet. 
Between the Missouri River and the Rocky Mountains there is 
a great swelling of the land, which to the ordinary observer is al- 
* Read before the Chicago Academy of Sciences, November 14, 1871. 
_ „ Entered according to Act of Congress, in the year 1872, by the PEABODY ACADEMY OF 
SCIENCE, in the Office of the Librarian of Congress, at Washington. 
AMER. NATURALIST, VOL. VI. 5 (65) 
