OF ARKANSAS. 117 
The succession of the 
rocks on the waters of 
3 | the Middle Fork of 
White river, is exhibited 
8 in the accompanying 
: diagram, in which the 
| 
Feet. 
Inches. 
i Sandstone, underlaid by shale? in/all, 50 to Pesthan of, oie bed a 
100 100 feet or more in thickness. dark grey, pyritifer ous 
limestone is shown, in- 
cluded in the shales at 
—— the base of the section. 
Several so-called “ sul- 
phur__ springs,”’_— rise 
through the black bitu- 
ae . . | minous shales, at the bot- 
to Archimedes, cavernous, and concretionary tom of the. sections, in 
602 mie Smes the central part of Wash- 
ington county. The wa- 
ter of one, which was ob- 
tained from John May’s 
place, one mile south of 
Fayetteville, was found 
by the application of chemical reagents, to contain, as its principal 
constituents : 
Sulphate of magnesia, (Epsom salts). 
Sulphate of alumina, a trace. 
Sulphate of iron, a trace. 
Bi-carbonate of lime. 
Bi-carbonate of magnesia. 
This water will act as a mild laxative. 
County surveyor Ross informed me that there has been some difficulty 
in running lines with the compass, in the valleys and along the spurs of 
some of the hills, with what is considered the true variation in this part 
of the State, of 8 deg.-30 min. The iron ores which I have seen on the 
surface, viz., limonite ores and protocarbonate of iron, do not affect the 
magnetic needles neither have ores of lead any influence on it: it is only 
native iron, iron ores containing a combination of peroxide and protoxide, 
in the proportion of about-69 per cent. of the former, and 31 of the latter, 
and magnetic iron pyrites, containing about 40. per cent. of sulphur and 
60 of iron, that attract the needle. Those localities will require, therefore, 
—)|e|oej_}s 
effi [yt | 
le |) \-]e 
[ 
302 Grey shale; pyritiferous limestone shale. 
| 
cI 
/ 
