DESICCATION OF SALINE MUDS 485 



phenomena connected with the desiccation of saline mud. These areas 

 are more or less completely covered with waters from the saline springs 

 in the spring and early summer. The wide expanse of mud-cracked sur- 

 face which late in the summer develops with the disappearance of the 

 water from the salt plains shows in certain areas peculiar little mounds 

 of saline clay (figure 9). These vary in height from a few inches to a 

 foot or more and over limited areas are spaced at intervals of 1 to 4 feet. 

 They differ from Goldman's "salt crusts" in being essentially clay with 

 only a trace of salt. Several of these mounds were cut into, all of which 

 showed at the base a core of dark vegetable matter which appeared to 

 represent a variety of bunch grass. Evidently the development of these 















Figure 10.— Mud-crack with corrugated Surface, Salt River, Northwest Territory 



Salt River miniature clay mounds has started through the agency of 

 small detached patches of grass or other vegetation which, gaining a tem- 

 porary foothold on the saline clay, were later overwhelmed with saline 

 efflorescence and incrustations and turned gradually into mounds of clay 

 or mud through the periodic leaching out of the salt, leaving behind the 

 argillaceous matter which accumulated with it. The capacity of saline 

 water for surrounding and incrusting any upright object with which it 

 comes in contact has been illustrated in the first part of this paper. Grass, 

 algas, or other vegetable materials would serve as nuclei for large saline 

 incrustations quite as well as the materials used in the experiments. It 

 ];ias also been experimentally shown that the basal layers of salt efflorescing 

 on mud draw up with them some of the mud. 



