GEOGKAPHY. 9 
rated by low, flat-topped ridges which are remnants of an earlier 
terrace system. The valleys of Little Laramie and Laramie rivers 
are especially wide and flat bottomed. A characteristic view of the 
Little Laramie Valley is shown in Plate III. The divide between 
these two valleys west of Laramie is a ridge 300 feet or more in 
height, containing a depression 200 feet deep, known as "The Big 
Hollow," which is 9 miles in length and 3 miles in width, with its 
longer axis trending west-southwest and east-northeast. Big Basin, 
northwest of Laramie, is similar to The Big Hollow, but is of less 
extent and lies at a slightly lower altitude. Other notable basins are 
occupied by Cooper and James lakes. 
DRAINAGE. 
The greater part of the Laramie Basin is traversed by Laramie 
River, which finally crosses the Laramie Mountains in a deep canyon 
and flows out across the Great Plains to join North Platte River. It 
rises in the Medicine Bow Mountains and other ranges in northern 
Colorado and receives various branches from the south and west. 
Little Laramie River is the principal branch, and Sand, Willow, and 
Fivemile creeks carry a moderate volume of water. Dutton and 
Cooper creeks are two small streams which head in the east slope of 
the Medicine Bow Mountains and empty into Cooper Lake. Prob- 
ably the water of this lake finally finds its way underground into 
Laramie River. The Laramie receives but few branches from the 
east; of these, Willow, Soldier, and Spring creeks and a stream 
northeast of Wyoming station carry a small volume of water. The 
northwestern portion of the region is drained by Medicine Bow River 
and its two large branches, Rock and Little Medicine Bow creeks. 
Medicine Bow River and Rock Creek (see PL IV) head in the north 
end of the Medicine Bow Mountains. Little Medicine Bow Creek and 
its branches, Sheep and Muddy creeks, head in the plains and 
mountain slopes to the north and northeast. 
A notable feature in the Laramie Mountains is the general eastward 
drainage, down the wide eastern slope of the range. Sybille Creek 
and North Laramie River drain small portions of the eastern side of 
the Laramie Basin and flow across the mountains in canyons. 
CLIMATE. 
Temperature. — The climate of the Laramie Basin presents the usual 
features of the northern Rocky Mountains and the higher Great 
Plains. It is dry and cool, is relatively uniform from year to year, 
and has a large percentage of sunshine. Meteorological records have 
been kept at the State university at Laramie since 1891, and their 
results, summarized on page 10, indicate the principal features. 
