Page:Report on the geology of the four counties, Union, Snyder, Mifflin and Juniata (IA reportongeologyo00dinv).pdf/294

266 F³. contains two ore beds, but neither of them seem to have been rich enough to warrant their being mined much. The upper one is said to have been about 16 inches thick, but was very largely a hard fossiliferous limestone containing little iron.

The Sand Vein was once very actively developed along its southern outcrop between Lockport and the eastern end of the ridge, the Glamorgan Iron Company being the last lessees of the property. Some 45,000 tons of ore were mined here for the Lewistown furnace prior to 1873; but there was no record obtained of what these mines furnished during the last 15 years. The bed was about 15″ thick and must certainly have been a very good ore. Stopes from 30 to 50 feet were made from water level to the top of the ridge, all of which space furnished soft fossil ore. In addition to this fact, the south dip after the bed passes beneath the water level, is so very gentle going towards the river, that a large quantity of soft ore was obtained by stripping the overlying shales and lifting the ore as in a quarry.

No developments have been made along the Blue Ridge and it is highly probable that the fossil ore beds here are both thin and siliceous. The same is true in a great measure of the Jack’s mountain outcrop, although a considerable quantity of fossil ore marks the presence of the Sand Vein ore bed on the mountain and would suggest the propriety of developing it. However there are but few gaps along the mountain flank to afford natural access to the ore bed by entering it from the ends, and the presence of much more favorably located ore in the anticlinal ridge of Ferguson valley has no doubt deterred any very extensive exploitation along Jack’s mountain.

Ferguson Valley Ore Ridge.—At the extreme eastern end of the ridge the Keever ore bank was opened on the northeast dip of the Sand Vein, which was found 16 inches thick, but with a rather shaly bottom. It was found largely as hard fossil ore and not rich in iron, so that the opening was soon abandoned. In the next mile west the ore ridge