228 FIELD COLUMBIAN MusEUM—GEOLOGY, VOL. I. 
EPSOMITE. 

NEAR WILCOX STATION, 65 MILES NORTH OF LARAMIE, WYOMING. 
MUSEUM No. M 6126. 
An account of the above occurrence of epsomite was given the 
writer by Prof. W. C. Knight of the University of Wyoming, in a 
recent letter. He writes: ‘‘A deposit of epsomite, which is of 
variable depth, covers an area of go acres near Wilcox Station, 
Albany County, Wyoming. Inthe spring the area is covered with 
water to the depth of a foot or more, forming a small lake, but on the 
advent of summer the water evaporates rapidly and an abundant 
deposit of beautifully crystallized epsomite is left.” 
A few ofthese crystals were received from Prof. Knight at the same 
time by the writer, but not being able to study them immediately, 
they became, through deliquescence, unfit for thorough crystallographic 
investigation. I have thought it desirable, however, to publish an 
account of the occurrence so that any who may visit the locality may 
improve the opportunity to secure material whose forms may admit 
of exact determination. The crystals received by the writer are from 
8 to 15 mm. in length and are of elongated prismatic habit. Many 
are doubly terminated and have pyramidal planes which plainly show 
sphenoidal symmetry. The habit of the crystals and the fundamental 
/ 
Pee me 
, 
/ z 
/ 

Fic. 6—Epsomite, 
forms are shown by Fig. 6. The determination of the pyramid 
z (111) depends on a measurement secured as follows: 
Measured. Calculated. 
Wive—=TIOoia = BO 301 fens 
While some of the crystals have only the simple development 
represented in the figure, others are evidently more highly modified, 
but owing to the deliquescence previously referred to, it was found 
impossible to determine the forms. 
