484 E. M. KINDLE SEPARATION OF SALT FROM SALINE WATER 



quarries numerous elevations occur rising from 1 to 3 inches above the 

 adjacent flat sun-cracked surface. These curious depressed little hum- 

 mocks vary from a few inches to a couple of feet in diameter and have a 

 highly irregular outline iji most cases. They are cut like the adjacent 

 surface by sun-cracks. 



These miniature hummocks on the mud-cracked beds of the Pamelia 

 limestone are probably related in origin to and are somewhat comparable 

 in appearance with the curious elevations found on the surface of the 

 mud in certain localities, known as "self-rising ground," on the playa 

 clays of the Southwestern States, which have been photographed by Dr. 

 M. I. Goldman. Concerning these photographs (figures 7, 8), which I 



Figure 9. — Mounds of Clay on Salt Plain icest of Fort Smith, Alherta 



am able to reproduce through the courtesy of Doctor Goldman, he writes 

 as follows: "I find in my notebook the following concerning the photo- 

 graph numbered 11 : '^Bulged salt crusts at edge of desert at Trego, hum- 

 mocks white, intervening fiat portions blue gray clay.' Evidently, there- 

 fore, the white portions on the picture are essentially salt, though they 

 would doubtless contain some clay impurity." 



Some features observed during a recent visit to the salt plains of Salt 

 River, jSTorthwest Territory, appear to fall in the same general category 

 with the Pamelia limestone hummocks and the "self-rising ground" of 

 the southwestern playas. Several hundred acres of the fiat plain in the 

 vicinity of the salt springs of Salt Eiver are entirely destitute of vegeta- 

 tion and afford exceptional opportunities in midsummer for observing 



