OF ARKANSAS. 103 
up Holman’s creek, associated with this black shale. The rocks, along 
this branch, lie too low in the geological formations to contain any work- 
able beds of coal. 
On this same stream, about nine miles north-west of Huntsville, the 
road leads, for half a mile, through barrens with a sandy soil, followed by 
prairie in which sandstone crops out about 10 miles from Huntsville. 
This prairie is bounded by wooded hills off to the south-west. 
Proceeding towards the north-west, the Archimedes limestone and asso- 
ciate shale are succeeded by chert and cherty limestone on the edge of the 
barrens; after which comes sandstone in the prairie. In the former, casts 
of Orthis crinistria? were found about four or five miles from Holman’s 
creek. 
This cherty limestone, which belongs, doubtless, to the lower division of 
the subcarboniferous group, has a considerable area in the northern part 
of Madison county, and possesses the peculiar lithological character of the 
most productive lead-bearing rocks of the adjacent part of south-western 
Missouri. 
Some lead ore has been found in the Moudey settlement, about four 
miles north of Huntsville; if it had its origin in this formation, it is a 
locality which should claim the attention of the miner, as will appear 
more fully in the next section, when treating of Benton county. 
This cherty limestone, containing a few entrochites, underlies the Brush 
creek barrens, and the spring at C. Fitches’, on the edge of these barrens, 
and close to the line between this county and Washington, wells up 
through the same description of rocks; these are analogous, and most pro- 
bably cotemporaneous with, the geological formation that underlies the 
barrens of Kentucky. 
BENTON COUNTY. 
In the extreme south-east corner of this county, along the bluffs of 
White river, the barren limestone formation, of which we had occasion to 
speak in the previous section, under the head of Madison county, forms 
conspicuous cliffs near the crossing of the road from Huntsville to Ben- 
tonville. On section 24,? township 18 north, range 19 west, (if this road is 
correctly laid down on the maps,) a hard, sheety black shale comes in under 
this limestone, having the appearance of the black shale of Wiley’s Cove, 
in Searcy county; but, probably, occupying a rather lower geological 
position in the subcarboniferous group; since that shale underlies the 
Archimedes and encrinital limestones in the upper division of the subcar- 
