GRIMSLEY. | Gypsum Mines and Mills. 65 
ALUMINITE OR AZTNA DEPOSIT NEAR DILLON. 
Another similar deposit is located three and one-half miles 
‘southwest of Dillon, in a low place near a small stream, and 
here again springs prove troublesome. Plate XX shows the 
actual working of this deposit. The cover is 10 feet thick, and 
the deposit is 5 feet, but near the top is a layer of 20 inches of 
sand and gypsum, which sets too quickly, and so is thrown out. 
Gypsum rock is not reported below this, but a heavy deposit is 
found on the hill about 50 feet above the gypsum earth. The 
material from this deposit is hauled to the mill close by, and is 
the property of the Altna or Aluminite Cement Plaster Com- 
pany. Mingled with the earth were shells and some bones, 
which were thought by the finders to be buffalo bones. Unfor- 
tunately these have been lost and cannot now be identified. 
ACME DEPOSIT AT RHODES. 
In Marion county, about seven miles south of Banner City, 
the Acme Cement Plaster Company owns a mill and a gypsum 
earth deposit similar to the others, which is represented in 
Plate XXI. Itis 6 to 10 feet thick, and is near a small creek. 
The gypsum rests upon sand, in which Professor Sharp found 
recent shells of types Planorbis and Physa. HKighteen feet below 
the top of the earth is a well-marked gypsum ledge. The actual 
working of this deposit is shown in Plate XXII. This mill has 
not been running since last spring. 
AGATITE DEPOSIT AT LONGFORD. 
The Agatite Company have another mill near a gypsum-earth 
deposit at Longford, Clay county, thirty-five miles northwest of 
the Dillon mill. This mill is shown in Plate XXIII. The de- 
posit is near a creek four miles east of the mill, and varies 
from 2 to 10 feet in thickness over an area of sixty acres, and 
is shown in Plate XXIV. Other gypsum earth deposits are re- 
ported from this same region and near Manchester. 
MICROSCOPICAL EXAMINATIONS. 
These gypsum deposits undoubtedly belong to the earthy va- 
riety of gypsum, called by the Germans Gypserde, Himmels 
mehl; Himmels mjol by the Swedish, and Gipsowaya muka 
