OF ARKANSAS. 5Q 



diggings, on Jemmy's creek, promises to afford sufficient silver to pay the 

 expense of extraction. 



The rocks of the lead region of Carroll county, near the Coka and 

 Mitchell diggings, dip to the south-west, so that the encrinital limestones 

 descend, in that direction, at the rate of about 100 feet to the mile; and 

 are near the level of the creeks, two miles south-west of the locality 

 represented in plate No. 4. 



FULTON COUNTY. 



In the townships of land, situated in the north-western part of this 

 county, the highest knobs are composed, like those in Marion and Izard 

 counties, of cherty masses, referable, probably, to the subcarboniferous 

 era, resting upon earthy, hydraulic-looking marls, limestones and shales, 

 on which the principal tracts of arable land are based. Such is the nature 

 of the strata in the " Rapp Barrens," between White river and the North 

 Fork, at an elevation of about 130 or 150 feet above these streams; and 

 corresponding in their lithological character to the strata of Marion county, 

 formerly made mention of, occurring 4 or 5 miles north-east of Yellville, 

 between the waters of Crooked, Jemmy's, and Fallen Timber creeks. 



The following strata were observed at elevations in ascending from the 

 North Fork to the general level of the country, in the vicinity of the Rapp 

 barrens, in the upper 80 feet of the ridge, which overlooks the Ripple of 

 the North Fork, near the Rapp barrens: 



At 380 feet: above the North Fork, varieties of crisp and agatized chert 

 prevail. 



At 375 feet: white-weathering magnesian limestone. 



At 370 feet: coarse-grained magnesian limestone and chert. 



At 365 feet: porous buhrstone and chert. 



At 300 feet: hard blocks of coarse-grained, glistening, siliceous rock, 

 intermediate between chert and sandstone. 



The strata of the lower part of the cliffs, along the North Fork, in the 

 vicinity of these barrens, are mostly composed of different varieties of 

 magnesian limestones and silico-calcareous rocks, which are remarkable 

 for the great differences which they exhibit in their capabilities of resisting 

 atmospheric vicissitudes; some layers being hard, compact and durable, 

 stand out prominently in overhanging ledges; others, crumbling away, 

 recede, even under the shelter and protection of more durable strata.* 

 Some of the layers possess a fine oolitic structure. 



* See Chemical Report for the analyses of these two different kinds of rocks. 



