GYPSUM. 197 



copper. It also occurs in nodular form and as incrustations in the clay. 

 There are no regular veins, as is the case in many mining districts, but the 

 copper occurs in beds. It was evidently precipitated from the sea water at 

 the time of the deposition of the clay beds. This copper will be of economic 

 value when works for its reduction shall be erected at the mines so that low 

 grades of ore can be used. 



IRON. 



The iron ore of the Permian formation is principally a carbonate of low 

 grade; it occurs in the red clay of the Wichita Beds in concretions. The 

 disintegration of the clays has caused these concretions to accumulate at the 

 bases of the precipices in large quantities, and in a convenient form to be 

 handled, if the ore, upon proper analysis, shall be found to contain sufficient 

 metallic iron to warrant the reduction. The red color of the clays is due to 

 the oxidation of the iron contained therein, but the amount of metallic iron 

 in the clays is very small. 



GYPSUM. 



The deposits of gypsum found in the red clays of the Permian strata are 

 the most extensive of any such beds in the United States. They are co-ex- 

 tensive with the Double Mountain Beds and the upper part of the Clear Fork 

 Beds. The beds are of thicknesses varying from that of paper-like sheets to 

 25 feet. There are all varieties, from transparent selenite to the massive 

 earthy kinds. Some of the beds of alabaster are very clear, and admit of 

 fine polish. There is enough gypsum in these beds to supply any demands 

 that could be made. 



