Page:Report on the geology of the four counties, Union, Snyder, Mifflin and Juniata (IA reportongeologyo00dinv).pdf/194

166 F³. exposed, for no streams cut through the high mountain wall so as to expose them: and the lower Clinton rocks, embracing the Tron sandstone series, occupy an area along the southern side of the township a mile wide and extending east and west for 6 miles.

The Iron sandstone ridge, capped with block ore, forms a prominent hill, broken by some few ravines south of Middleburg. This rock occurs geologically about 150′ beneath the Ore sandstone, which forms a similar ridge lying further north. Portions of the Iron sandstone in some localities are quite rich in iron, the whole series varying between 10′ and 15′ in thickness. About a mile southeast of Paxtonville, on property of the Bloomsburg Iron Company, there is an old open cut on the crest of the ridge, where the block ore, some 8′ or 10′ thick, was formerly mined for the Beaver furnace. About 4′ or 5′ at the bottom of the bed is fairly rich in iron, though siliceous; but when worked, nearly 10′ of material was blasted out here and sent to the furnace, which could not have proved but disappointing and highly siliceous. The open cut is about 250′ long and the bed shows a dip of 45°–50° N. W. The floor is sandstone, rather bulgy and irregular. The best ore was a hard dense reddish material, yielding about 35 per cent. of iron and capped with seams of slate and ferruginous sandstone, carrying blocks of ore from 2” to 6” thick, much of which was mined and shipped with the better 4′ at the bottom and smelted both at the Beaver furnace and at Bloomsburg.

The Danville fossil ore bed was opened on the north flank of this ridge, at its eastern end; but it was lean also and only 6″ thick. Further north the Sand Vein is reported to have been opened in a monkey drift and found 2′ thick, carrying two layers of slate and furnishing a lean ore.

Between the Block ore ridge and the Ore sandstone there is a smal] synclinal, showing at Paxtonville a north dip of 45° and occupied by Clinton shales, whose dip flattens going westward and permits the ore measures to remain in the synclinal.

At Bobb’s run the block ore shows at water level in a