OF ARKANSAS. 63 
LAWRENCE COUNTY. 
Near the forks of the Jackson and Smithville road, some chert ridges, 
measured, were found to have an elevation of about 80 to 100 feet above 
the drainage of the country. 
On Morton’s creek, near Morgan’s mill, there is some zinc, which may 
prove valuable, if fairly opened and exposed, as the surface indications 
are somewhat encouraging. . 
The chert of the ridges along Morton’s creek is mostly dull and impure, 
with little or no true chalcedony. 
In the cuts of the stream, grey and white varieties of magnesian lime- 
stones crop out, associated with a white rock, which has the appearance 
of a calciferous sandrock. 
The same character of rocks prevails to the Big Lick. South of that 
locality, some porous buhrstones are intermixed with the dull, impure, 
earthy chert, and a white magnesian limestone was observed cropping 
out, approaching, in its character, the so-called “ Cotton Rock.” 
On Machine creek, some zinc ore has been discovered, and a few loads 
hauled over to the zine furnace, in Lawrence. i 
E. W. Houghton explored for lead ore on Stennett’s creek, in this 
county, and obtained considerable lead ore, but abandoned the diggings, 
probably, because there was no lead furnace to smelt the ore. 
The main zinc deposits of Lawrence county, on which the principal 
dependence is placed for supplying ore to the furnace now erected at 
Calamine, are the so-called Hoppe diggings, on section 19, township 16 
north, range 2 west. 
The ore here is very accessible, being, in some places, only one foot 
beneath the surface. Jt has been followed down 18 feet, and found occu- 
pying interstices between isolated corroded masses of limestone, and inter- 
mixed with, and imbedded in red clay. The width of the excavation was 
about 25 feet. The associate limestone is of a light grey color, with 
strings and thin veins of disseminated ore, which comprises mostly those 
different varieties of carbonate of zinc, described in works on mineralogy, 
under the name of “calamine” and “smithsonite.” 
The chemical analyses of these ores, made by Dr. Elderhorst, in my 
laboratory, gives an average yield of 51.7 per cent. of oxide, which is 
equal to 41.5 per cent. of metallic zinc in these carbonates. 
Intermixed with the carbonates there is also some zinc blende, which 
will yield, when freed from adhering gangue, nearly 66 per cent. of metal- 
lic zinc; but this ore, though containing a larger proportion of zine than 
