12 UNIVERSITY OF COLORADO STUDIES 



in Gunnison and Saguache counties, as also the main stream, flow 

 through rather narrow valleys and canyons, over rough stream beds, 

 making the Gunnison one of the most picturesque and turbulent 

 rivers of the state. The South Fork of the Gunnison leaves the high- 

 land through the Grand Canyon of the Gunnison, meeting the North 

 Fork near Delta. At Delta the Gunnison receives a large tributary 

 from the south, the Uncompahgre River. 



The summarized data concerning the river systems of the state 

 are given in the following table (I). These data should be used in 

 conjunction with the maps. 



Lakes 



Considered biologically the natural lakes of Colorado are of two 

 types, the high mountain lakes and the plains lakes. Those of the 

 first group are characterized by cold, clear water containing very 

 little solid matter in solution, and almost none in suspension. These 

 lakes are numerous throughout the mountains and usually have an 

 altitude of more than 8,000 feet. Several of them are of considerable 

 size although many are less than a mile across. Of the larger lakes 

 the most prominent are Twin Lakes in Lake County, Grand Lake in 

 Grand County, Marvine and Trapper's lakes in Rio Blanca County, 

 John Lake in Jackson County and Santa Maria Lake in Mineral 

 County. 



The plains lakes usually contain an appreciable quantity of 

 alkali in solution, are sometimes turbid with suspended material 

 and vary much in temperature with the season. Many such lakes 

 are found in the northeastern portion of the state and several in the 

 upper part of the San Luis Valley. In this class must also be in- 

 cluded, as regards the fishes contained, the various artificial reservoirs 

 in the plains and foothill regions of the state. 



Systematic Account of the Fishes of Colorado' 



Class PISCES 



Aquatic poikilothermous vertebrates with gills functional throughout life, 

 usually with paired lateral fins, without digitate limbs, with a lower jaw. 



» For definitions of the technical terms see glossary, p. 131. 



