A STUDY OF TWIN LAKES, COLORADO, WITH ESPECIAL 

 CONSIDERATION OF THE FOOD OF THE TROUTS." 



By CHANCEY JUDAY, 

 Wisconsin Geological and Natural History Suii'ey. 



PHYSICAL CHARACTERISTICS OF THE LAKES. 

 LOCATION. 



These two beautiful sheets of limpid water lie in the southern part of Lake 

 County, Colorado, about 15 miles soutli-southwest of the city of Leadville, nestled at 

 the base of the highest mountains in the state. Viewed from the east, they have 

 for a background the loftiest peaks of the Sawatch Range, which extends north and 

 south immediately behind tiiem. Rising from the lake basin on the northwest are 

 spurs and ridges which lead up to Mount Elbert. This mountain has an altitude of 

 14,421 feet (4,395.5 meters), and is only 3 feet lower than Mount Massive, its 

 neighboring peak on the north, which is said to be the highest in Colorado. La 

 Plata peak, rising but a short distance southwest of the lakes, has an altitude of 14,342 

 feet (4,371 meters), while between La Plata and the lakes are loft}- ridges with peaks 

 having an altitude of probably 13,000 feet (4,000 meters) or more. As the ridges 

 extend down to the lakes, the southern shores are very steep. The general contour 

 of the country surrounding the lakes is shown in plate iii. 



OKICJIN AND SIZK. 



The lakes lie a short distance below the mouth of Lake Creek Canyon. This 

 canyon extends westward l)etween Mount Elbert and La Plata, and there are many 

 evidences to show that it was once occupied by a glacier which probably came down 

 and joined the glacier that occupied the canyon of the Arkansas River. Much of the 

 debris brought down b}' the Lake Creek glacier was deposited in the lateral moraines 

 which form high ridges on either side of the lower valley. Thus the lakes are 

 entirely surrounded by morainal detritus witli no rock in place exposed along the 

 shores except for a short distance along th(> north shore of Lower Lake. The glacier 

 was no doubt active in scooping out the lake basins, and then as it receded two 

 terminal moraines were formed, one which maintains the water in Lower Lake and a 

 second one, about 225 yards (2oO meters) wide in its narrowest part, which separates 

 the two lakes. These latei-al and terminal moraines are well shown in sketch maps 

 by Holmes in Hayden's Report for 1874 (between p. 48 and 49). 



"Study made for the United States Bureau of Fisheries during the gunnners of 1902 and 190,3. 



151 



