238 G. P. GRIMSLEY — GYPSUM DEPOSITS OF KANSAS. 



Neosho epoch the whole series of rocks — gypsum, shales, and lime- 

 stones — was elevated and joined to the continent. 



The water channels so well shown in the Winter's mine and the veins 

 with the beautiful transparent crystals, in the Fowler mine indicate that 

 water solution has produced marked effects in the later history of the 

 deposits, effects which are even now in operation. The subterranean 

 circulating waters have dissolved the gypsum, formed channels, and re- 

 deposited much of the material in fissures in the form of transparent 

 crystals, or near the top as needles of satinspar. A glance at a map of 

 the gypsum area shows one that a very large quantity of the rock has 

 been removed by stream erosion, thus revealing to man the store of 

 mineral wealth in these hills. 



The geological sections show that the gypsum lies about 20 feet above 

 the Cottonwood Falls limestone, which is taken by Prosser as the base 

 of the Permian, and the gypsum belongs near the middle of the Neosho 

 division outlined in his paper. 



The cover of compact shales has served to protect the underlying 

 gypsum from solution by circulating water to a considerable extent, thus 

 explaining the absence of the marked solution effects noted in the area 

 farther south. 



CENTRAL AREA. 



The evidence at hand indicates that the central Kansas basin is con- 

 tinuous with the northern and had the same origin — that is, a deposi- 

 tion in a shallow bay cut off from the western sea by a barrier. The 

 dip of the rock is westward, and a change in conditions brought about a 

 second deposit of gypsum, separated from the first by 100 feet of sandy 

 sediment. At the Solomon mine the gypsum, intercalated with beds of 

 shale, affords good evidence of the alternating conditions of gypsum- 

 forming and sedimentation. 



Abundant traces of salt occur in springs and in wells near the Solomon 

 river, but no salt is associated directly with the gypsum. In the Hutch- 

 ison-Kingman-Lyons region occur the large salt deposits which have 

 placed Kansas in the front rank of salt-producing States of the Union. 

 These beds belong to the Permian (at a lower level than the gypsum but 

 farther out in the bay in the direction of the dip), and they represent a 

 later stage in the gulf evaporation. The Saline-Dickinson gypsum de- 

 posits belong to the Marion division of the Permian, for the Dakota red 

 sandstone is found on the hills south of Gypsum City, 300 feet above the 

 lower gypsum. 



The shales and gypsum in the Smoky Hill river region are irregularly 

 folded and broken as a result of settling, possibly by the leaching out 



