UPPER ARKANSAS YALLEY. 349 



Lake Moraine is situated in a valley descending from the col between 

 Pikes Peak and Bald Mountain. A glacier but little more tlian a mile in 

 length occupied this basin. It left jjrominent lateral moraines near 200 feet 

 -above the bottom of the basin, and formed a massive terminal moraine near 

 one-fourth of a mile long and 100 or more feet deep. There is a depres- 

 sion across the terminal moraine, in which a stream flows. No glacial 

 gravel appears in the valley below, which is very steep, so that the over- 

 wash of the glacier would soon be eroded. In the bottom of the depres- 

 sion in the terminal moraine appears a mass of fine sediment, mixed with 

 occasional bowlders, which, under the microscope, is seen to consist of glacial 

 rock flour. 



This little glacier was situated between 10,000 and 11,000 feet eleva- 

 tion. The snowfall of this range is much less than that of the Continental 

 Divide. The temperature was low even in summer. The glacial waters 

 flowed so sluggishly that even much of the rock flour did not get beyond 

 the terminal moraine. 



A little glacier formed on the east side of Pikes Peak and formed a 

 diminutive moraine which now holds in a lakelet. 



SOUTH PARK. 



A number of glaciers originated in the Mosquito Range and flowed 

 eastward into the South Park. Some of them were near 10 miles in length. 

 They left moderate-sized moraines and plains of glacial gravel that extend 

 15 miles down into the open park. These plains are marked "scattered 

 drift" on Hay den's maps. In most cases where I have had opportunity to 

 examine a region thus marked they end in the mountains in a glaciated 

 region and are frontal plains of glacial sediments. The proportion of 

 glacial gravel to moraines is here probably greater than in the Arkansas 

 Valley. 



ROARING FORK. 



The valley of the Middle Branch of the Roaring Fork contained a 

 glacier 15 or more miles in length. The moraines of this glacier can be 

 seen from the Colorado Midland Railway. Lake Ivanhoe, along this rail- 

 way, is held in by a morainal dam. Below the terminal moraines the 

 valley was left covered with a deep sheet of water-rolled sediments which 

 dias now been eroded to a depth of 30 or more feet. 



