GYPSUM BEDS. 91 



such is not the fact, as all the principal branches above Cache creek 

 have their origin in tbe eastern borders of the table lands of New 

 Mexico, where tbere are no mountains. We, however, observed frequent 

 and copious rains in the vicinity of the Witchita mountains during the 

 season of the June flood; and I am of the opinion that here is the 

 source whence much of the water is derived. 



As the water in the river has a very bitter and disagreeable taste, it 

 has been conjectured that it passed in its course through extensive salt 

 plains ; but this I also found to be an error. We saw no deposite of 

 chloride of sodium in the vicinity of the river; the peculiar taste being 

 communicated by ingredients that it receives in flowing for a hundred 

 miles over a gypsum formation. An analysis of this water, under the 

 direction of Dr. Clark of Amherst College, gives the following results, 

 from which it will be seen that the per-centage of salt is small :* 



Weight of water in fluid ounces ------ 4. 



Weight of water in fluid grammes ----- 127.800 



Weight of chlorine present ------ .051 



Weight of lime .033 



Weight of sulphuric acid - -'.-'- - - - .095 



Sulphates of soda and magnesia ------ .168 



Regarding the lime as a sulphate, and the residue of sulphuric acid as 

 united with magnesia, and the chlorine as united with the sodium, we 

 have the following results : 

 Weight of sulphate of lime ------ .080 



Weight of sulphate of magnesia ------ .073 



Weight of chloride of sodium - .084 



Weight of the whole .237 



Per-centage of matter in solution ----- 19 



This gypsum range forms an immense belt, which extends across the 

 country for some four or five hundred miles. Col. Long speaks of seeing 

 it upon the Arkansas ; and I have myself passed through it at four other 

 different points south of this, embracing a range of some three hundred 

 miles. It is regarded by Dr. Hitchcock as the most extensive deposite 

 of this mineral in North America. I have everywhere found it char- 



*I have understood, since our return, that the Indians have recently discovered 

 a deposite of salt (chloride of sodium) about three miles to the south of our return 

 rouce, near the western extremity of the Witchita mountains. 



