OF ARKANSAS. 103 



up Ilolman's creek, associated with tins 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 Iluntsville, 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 Iluntsville. 

 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 chcrty limestone on the edge of the 

 barrens; after which comes sandstone in the prairie. In the former, casts 

 of Orlhis crinistria? were found about four or five miles from Ilolman'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 cncrinital limestones in the upper division of the subcar- 



