108 DESCRIPTION AND ANALYSIS OP A MINERAL, ETC. 
ART. XVII DESCRIPTION AND ANALYSIS OF A MINERAL 
A SALINE INCRUSTATION, AND A BARK, BROUGHT 
FROM THE COUNTRY LYING BETWEEN SANTA FE, AND 
THE HEAD WATERS OF THE ARKANSAS RIVER. 
By William Procter, Jr. 
The three substances which form the subjects of this essay 
were brought to this city by J. Gregg, an intelligent gentle- 
man who trades with Santa Fe, in Mexico. The specimens 
severally were accompanied by an outline of their locality, 
etc., which has been inserted previous to each description,* 
It would add greatly to our knowledge of the productions 
and resources of that section of country, as well as of other 
parts of the far west, if the same interest was manifested by 
all those who are engaged in the western trade beyond the 
Mississippi. 
The following remarks were attached to the mineral, viz : 
"This mineral is found in inexhaustible quantities on both 
sides of the Canadian fork of the Arkansas river, about three 
hundred miles above its junction with the latter. I have seen 
several huge solid rocks of it, containing several thousands of 
cubic feet each ; and, indeed, along the waters of the Cana- 
dian, for many miles, there is no other rock. The hills are 
covered, the vallies are strewed, and the rivulets are lined 
with it. It occurs of various qualities from the coarse appear- 
ance of ordinary plaster of Paris, to the glittering gypsum (se- 
lenite.) The latter is found, composed of thin laminae, which 
may be slit into sheets. 
The same quality, found in the vicinity of Santa Fe, is used 
for window panes ; and the coarser article (also found there,) 
burnt, makes a beautiful white-wash, which is also used by the 
Mexicans." 
* It is due to Alexander Fullerton, Jr., druggist of this city, to state that 
it was through his instrumentality that the substances above treated of 
were obtained from his friend J. Gregg. 
