1881.] - ^^* [Stevenson. 



Metallic iron 43.825 



Sulphur 0.029 



Phosphorus 0.9'26 



Insoluble residue 19.910 



Ore from another locality was mined for "White's forge on Moccasin 

 creek, and it is said by Mr. White to have proved even better than the ores 

 from Moccasin ridge. 



The Lower Helderberg is fairly well shown at little more than 2 miles 

 east from Moccasin gap, where a fine grained sandstone, almost a true grit, 

 rests on the Medina conglomorate. It contains many fossils, mostly indis- 

 tinct, among which are Spirifer and Platyceras, nearly allied to Lower 

 Helderberg forms. This rock shows no traces of iron ore, but immediately 

 above it is a fossiliferous brown hematite, which has evidently replaced a 

 limestone bed. The ore is bulky, and consists chiefly of casts of a Favosites, 

 which is somewhat coarser than Favosites helderbergice, and resembles more 

 a form occurring in the Coniferous. A cyathophylloid coral was obtained 

 from the ore, but it has been misplaced. No other exposure was found. 



The Hamilton shales are exposed at the mouth of Moccasin gap and 

 thence to a considerable distance up the side of Brushy mountain. Above 

 these are the Chemung sandstones, containing Spirophyton and Spirifera 

 disjuncta, and forming the crest of Brushy ridge, the first ridge of Brushy 

 mountain. The second ridge of that mountain is made up of Lower Car- 

 boniferous rocks, which continue along the Reedy creek road, to say a mile 

 beyond the North Fork of Holston river. They describe a synclinal at the 

 river. The abutments of the river bridge were constructed of rock from 

 one of the higher limestones, which is composed almost wholly of Fene- 

 stella. The highest beds of the Lower Carboniferous are mostly bluish 

 grits, with some impure limestones, and are well exposed along the road 

 as it follows a little ravine beyond the Holston river. 



The fault of North Fork of Holston is reached along this road at about a 

 mile from the river or near the head of the narrow gap just referred to. This 

 uplift brings the limestones and cherts of the Knox group again to the sur- 

 face and these continue as the surface rocks to the Tennessee line. Their 

 features are the same as on Moccasin ridge. 



A " poor valley " between Clinch movintain.and the first ridge of Brushy 

 mountain, extends from the Tennessee line to far beyond the limits of this 

 reconnaissance in Washington county. The Hamilton shales are exposed 

 at many localities in it, but the succession of the group is obtained best 

 by tying the partial section made in Moccasin gap to that made along the 

 railroad grade between Mendota and the North Fork of Holston. The es- 

 timated thicknesses are as follows : 



1. Dark sandy shale, fossiliferous, shown in the railroad 



excavations 130' 



2. Yellow to ash colored shales, mostly well exposed in 



the railroad excavations, but the base seen only on 

 the Abingdon road between Mendota and Moc- 

 casin gap ; dip 45 to 50 degrees 550' 



