GRIMSLEY. | Gypsum Mines and Mills. 55 
the water falls over a limestone ledge, Plate XII, shows 3 feet of 
blue shales at the bottom, covered by 4 feet of buff limestone in 
two courses, filled with the small shells of Fusulina cylindrica, 
or the wheat-grain fossil as it is commonly termed. Over the 
limestone 3 feet of shales are filled with fossils of the species 
Seminula argentia, Chonetes granulifera, Productus semireticulatus, 
Derbya crassa, crinoid stems and other forms. Above the fos- 
siliferous shales are found 15 feet of buff non-fossiliferous shales 
and thin limestones. This lower stratum is the Cottonwood 
limestone, covered by the Cottonwood shales marking the sum- 
mit of the Carboniferious series in Kansas. The top of the 
Fusulina limestone is about 30 feet (by barometer) below the 
bottom of the gypsum at the Great Western mine. The lime 
rock is quarried for building stone near the Union Pacific depot 
at Blue Rapids, and it is found in other ravines, always below 
the gypsum, so that the latter is of Permian age, according to 
the accepted elassification of the Kansas rocks already outlined 
in this paper. 
The gypsum rock at the Great Western mine possesses the 
same sugary texture as the rock at Fowler’s and resembles it 
very closely. ‘There is, however, a striking difference in the 
absence of the cutters and perfect crystals. The satin spar layer 
on top is usually thicker than at Fowler’s. The company has 
applied the name of crystal rock on account of its loose texture 
and brilliant surfaces when placed in the light. The rock is 
hauled in small cars over an elevated platform to the upper 
portion of the mill, which is on a level with the mine entry, as 
shown in Plate XIII. 
WINTER'S MINE. . 
On the bank of the Little Blue, two miles west of Blue Rapids, 
is located the Winter mine, shown in Plate XIV. The rock 
was formerly obtained by stripping and a very considerable area 
was thus worked out, but as the cover became thicker back 
from the river it was thought to be more economical to mine by 
running an entry into the hill. This entry is about 15 feet 
above the level of the water, and runs east about 900 feet into 
the hill. The double-entry system of mining is used, with 
