22 KANSAS: UNIVERSITY QUARTERLY. 
At Hope, twenty miles southeast, is located the only other mine 
in the rock gypsum in the central area. This is owned by the Kan- 
sas Cement Plaster Company, and they now obtain the rock from a 
fourteen foot stratum at the bottom of an eighty foot shaft. This 
rock is white, and much of it is traversed by wavy, dark lines, 
which give a gneissoid appearance, and the plaster made from it is 
sold under the name of ‘‘Granite Cement Plaster.” The lower 
part is compact and contains the rounded crystals of selenite, as in 
the mine at the north. Through this region there is another stra- 
tum five feet in thickness and roo feet higher, but it is not worked 
at the present time. 
SECONDARY DEPOSITS. 
Most of the plaster mills in this central area use the earthy gyp- 
sum deposits, which occur at various places in the region. There 
are five of these known. The first of these was discovered in the 
spring of 1873, near Gypsum City, by Mr. John Tinkler, in running 
a fire guard around a field. Two years later he calcined some of 
the dirt, as it is locally called, in an ordinary thirty-eight gallon 
kettle and used the plaster in the cellar of his house, where it still 
remains in good condition. In 1889, he, with others, built a mill 
at the edge of town, but it is no longer used. The deposit covers 
an area of twelve acres with an average thick of eight feet. It 
consists of a loose, granular dirt, of light ash gray color when dry, 
and it is readily shoveled into cars. It is thus directly calcined 
with less labor and expense than is the case with the solid gypsum 
rock. 
A number of years after the discovery of this deposit Mr. Got- 
lieb Heller discovered a similar deposit fourteen miles east near 
Dillon station. Another deposit is located three and one-half 
miles southwest of Dillon, and is five feet thick. In Marion county, 
about six miles south of the last deposit, the Acme Company owna 
mill and similar deposit which is six to ten feet thick. The 
Agatite Company have another mill and deposit at Longford, in 
Clay county, thirty-five miles northwest of the Dillon mill. 
All of these deposits lie in low, swampy ground, and strong 
gypsum springs are usually found in them. In most there is a 
ledge of rock gypsum at the same level or ten to twenty feet below. 
The presence of recent shells and bones near the bottom of these 
deposits shows they are recent in age. 
MEDICINE LODGE DEPOSITS. 
The southern Kansas gypsum, with its continuation in Oklahoma 
and Texas, forms the largest area in the United States. Near 
