8 - LARAMIE BASIN , WYOMING. 
greater part of the area is thinly settled, but as the population 
increases there will be great need for additional water supply. The 
surface waters at many points are not satisfactory for domestic use, 
so that underground waters from artesian wells may prove important. 
The geology of the southern half of the area had been set forth in 
a general way in the report of the Fortieth Parallel Survey, but it was 
necessary to make a more detailed classification of the formations, 
to measure their thickness, and to adjust the boundaries and structure 
to a more accurate base map, in order to obtain a reliable basis on 
which to make predictions in regard to the underground waters. 
Incidentally, attention was given to various mineral resources which 
have been developed in the region, although these have been treated 
to some extent in bulletins of the State university. The base of the 
map (PL I) which accompanies this report is the result of recon- 
naissance surveys, except for the portion south of latitude 41° 30', 
which is condensed from the maps of the Laramie, Medicine Bow, a 
and Sherman quadrangles of the United States Geological Survey. 
GEOGRAPHY. 
CONFIGURATION. 
The Laramie Basin is a wide rolling plain lying between the Lara- 
mie Range on the east and the Medicine Bow Mountains on the 
southwest. To the northwest lie the Freezeout Hills and various 
nigh ridges and the valley of Medicine Bow River. The Laramie 
Mountains are the northern continuation of the Front Range of the 
Rocky Mountains; they range in altitude from 8,000 feet in some of 
the lower passes to about 10,000 feet in Laramie Peak. The Medi- 
cine Bow Mountains are an extension of one of the inner ranges of 
the Rocky Mountains, which, in a portion called the " Snowy Range," 
rises to an altitude of 12,000 feet. The altitude of the Laramie 
Basin varies from about 7,000 feet in its northern and central por- 
tions to 7,500 feet near the Colorado line. The length of the basin 
is 90 miles, and the width of its wider portion is about 30 miles. 
The Laramie Mountains on the east rise in a long zone of moderate 
slopes; the Medicine Bow Mountains on the west are precipi- 
tous and have their continuity interrupted by some high outlying 
masses, of which Jelm and Sheep mountains are especially steep and 
conspicuous. The Laramie Mountains are crossed by the deep can- 
yons of Laramie and North Laramie rivers, north of which they rise 
into the prominent range culminating in Laramie Peak. (See PL 
II, A.) The range is also crossed by the valley of Sybille Creek and 
by several wind gaps. 
Although the Laramie Basin presents considerable variety of con- 
figuration, it consists mostly of broad, shallow, terraced valleys sepa- 
a In preparation. 
