104 GEOLOGICAL RECONNOISSANCE 



boniferous group, while this succeeds, in the descending" order, the barren 

 cherty limestone of the lower division. From SO to 35 feet of this shale 

 are seen in section, not only along the bluffs of White river, but also on 

 Hickory creek, about a mile to the west. At both localities, the shale is 

 overlaid by the barren limestone, which, on White river, forms cliffs of 80 

 to 100 feet. 



I have never seen, in any of my previous surveys in the western states, 

 amongst the subcarboniferous rocks, shales possessing the solidity and 

 hardness of the shales of Wiley's cove, or those of the south-east part of 

 Benton county, which may be almost entitled to the appellation of slates, 

 though not durable enough for roofing purposes; in this respect, these' 

 shales resemble, in lithological character, the hard, black, sheety shale or 

 slate of the Salt river valley, in Kentucky, and at the base of the knobs 

 of Floyd county, Indiana, belonging to the devonian period; which slates 

 are the representatives, probably, of the « Gennessee slate" of the New 

 York Reports. The superposition and association will undoubtedly place 

 both the shales of Wiley's Cove and Hickory creek, in Benton county, as 

 members of the subcarboniferous group. The fossils found, as yet, in 

 these shales, are too imperfect, and too few, to enable one to judge, from 

 them alone, of the age of these Arkansas shales; we are, therefore, obliged 

 to resort, for the present, to order of superposition for a solution of °the 

 problem. 



The ascent from White river, up the ridge, on the west side is 310 feet; 

 the road runs over chert, derived from the disintegration of the cherty 

 limestones, overlying the aforementioned black shale. In this chert are 

 found some of the disjointed disks of oval-shaped stems of platycnTms; 

 and at the Osage spring, the fountain head of Osage creek, it contains 

 Productus punctata, and the same species of reticulated, fossil corallines 

 which characterize the cherty limestone in the barrens of Kentuckv and 

 Tennessee. 



The lands between White river and Bentonville, are mostly oak bar- 

 rens, interspersed with prairie. 



Samples of soil were taken from Benton county, for future chemical 

 analysis, from the Hon. A. B. Greenwood's farm, near the town of Ben- 

 tonville. 



The oak and hickory timber which has now sprung up on the borders 

 of the present prairie, is mostly of a growth as recent as the settlement of 

 the country; since the greater portion of this part of Benton county was, 

 before that time, open prairie, with, here and there, thickets of low bushes 

 \* est of Bentonville, there is a mulatto soil, somewhat different in its 

 character from that immediately around Bentonville, and very productive 



