OF ARKANSAS. 109 
sounded hollow under the horses feet, marking, no doubt, the roof of some 
cavernous space in the underlying limestone. It is not improbable that 
this spot may be on the line of some crevice, and, if within the sphere of 
action that produced the metalliferous deposits of Newton county, Missouri, 
might lead to sources of cotemporaneous ore beds. The apparent west 
north-west bearing of the lead mines of south-western Missouri would, 
however, rather indicate their course north of this locality. 
The cavernous nature of the limestone, of this part of Benton county, 
is also indicated by the sinking of a branch of the Corner spring, that 
runs by the Burrow farm, beneath the surface, afew hundred yards below 
the house on this farm. 
The white, soft, decomposing chert of the barrens south of Beatty’s 
prairie, has casts and impressions of reticulated corallines, similar to those 
of the corresponding formations in Kentucky and Tennessee. These 
fossils were also observed, in greater abundance and perfection, near the 
centre of township 18 north, range 32 west, in the materials thrown out 
of a well. 
The soil of this part of Benton county appears to be well adapted for 
wheat, and, having a substratum of red clay, which, no doubt, will be 
found to have fertilizing effects, the productiveness of the surface-soil, by 
judicious management, need not be materially impaired, even by continu- 
ous culture. This country is well watered by fine springs, that issue from 
the south-west slopes of the cherty limestone. 
The greater part of Benton county is, therefore, based on this member 
of the subcarboniferous group, except in the higher grounds, where the 
flat oak woods prevail; there the barren limestone and chert is overlaid 
by shaly rocks and a kind of buhrstone and cherty sandstone. 
