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



lowing pages I wish to present some of the more important results of that 

 work which are of general interest. 



Among the minerals of commercial importance in Kansas, gypsum oc- 

 cupies a prominent place, and has attracted the attention of prospectors 

 and geologists for many years. Today, on account of the wide extent 

 and purity of the deposits and the skill in manufacture, Kansas stands 

 first among the states in the value of gypsum products. 



In 1869 the Blue Rapids Town Company made a reservation of the 

 Blue River gypsum deposits before selling their lands. Mudge briefly 

 described in the First Annual Report of the Geological Survey of Kan- 

 sas (1866) the gypsum deposits of the state, but he did not attempt to 

 give their origin or age. This description appears in a number of his 

 later reports with little or no change. In 1885 St John* describes im- 

 mense beds of gypsum in the uppermost measures of the Carboniferous, 

 which occur over a belt many miles wide across Kansas, with a thickness 

 of 15 feet in the northern part of the state. In a later report f on the 

 geology of southwestern Kansas the gypsiferous beds of that region are 

 stated by St John to be doubtfully Triassic. Cragin,J in 1885, places the 

 northern deposits in the Permo-Carboniferous and the southern beds in 

 the Benton division of the Cretaceous. He ascribed their origin to the 

 evaporation of a large saline lake which had no outlet. Later § he con- 

 cluded that it was rather a gulf or sea formation than a lake deposit, and 

 that it was Dakota in age. 



In 1892 the late Robert Hay || devoted considerable space to gypsum 

 in his paper on the " Geology and Mineral Resources of Kansas." He 

 placed these northern deposits in the Permo-Carboniferous, and was the 

 first geologist to describe the secondary gypsum dirt deposits of central 

 Kansas. In a brief paragraph on this formation he gives the origin as 

 due to the wash of adjacent deposits of gypsum, clay, limestone, and 

 sandstone. 



More recently Professor Cragin,^[ in an article on the Permian system 

 of Kansas, states that the lower Permian of northern Kansas contains 

 gypsum and rock-salt, and that the deposits of central Kansas belong to 

 the lower Permian, or his Big Blue series. The southern Kansas deposits, 

 described under the name of Medicine Lodge gypsum in his paper, are 

 placed in the upper portion of the Permian, called the Cimarron series. 



* Fourth Biennial Report of Board of Agriculture. 



•f Fifth Biennial Report of Board of Agriculture. 



X " Notes on the Geology of Southern Kansas," Bull. Washburn College Lab. Nat. History, 

 vol. i, no. 3, p. 85, 1885. 



g " Further Notes on the Dakota Gypsum of Kansas," Bull. Washburn College I^ab. Nat His- 

 tory, vol. i, no. 5, p. 166, 1886. 



I| Eighth Biennial Report of Board of Agriculture. 



fl Colorado College Studies, vol. vi, 1896. 



