836 KEMP AND KNIGHT — LEUCITE HILLS OF WYOMING 



tlie eastern side of the ridge in forms that stimulate glaciers with great 

 vividness. Figure 3 of plate 43 is from a photograph. The sand has 

 been derived from the erosion of the sedimentaries, but when placed 

 under the microscope it shows distinctly its wind-bloAvn character. The 

 dunes are from 3 to 6 miles wide and, with but few interruptions, extend 

 eastward to the North Platte river. 



