Page:Report on the geology of the four counties, Union, Snyder, Mifflin and Juniata (IA reportongeologyo00dinv).pdf/417

Rh signed the name of Peru sandstone. It is not fossiliferous, and in Huntingdon county contains pockets of iron ore.

The Lewistown limestone belt on the north side of the ridge is still quite wide, but shows only southeast dips of 25° and 30°. Its top layers are cherty and lean, but better stone has been quarried near the center of the series, where, however, the best beds seem to lie still in the bottom of the opening.

A second quarry, still further up the ravine, shows about the same features and neither opening ever seemed to have been very actively or economically worked. Both were idle when visited and were probably only worked periodically for the supply of local lime.

A little of the Marcellus limestone shows at Peru and the Marcellus black slate shows in the first bend of the road east of the mills and continues to border the road eastward to Tuscarora township, In the gap north of the school house a little over a mile east of Peru mills, the local anticlinal axis has expired completely, the dips being uniformly southeast about 30°.

The upper portion of the limestone formation is still quite slaty and the more solid members weather with rough surfaces and show a strong northwest cleavage of 60°. Limestone has been quarried a little east of this gap at M. Dougherty’s; and upon the crest of the ridge a mile west of the Tuscarora line, some little siliceous iron ore was derived from the Oriskany sandstone formation.

A section south from this point across the Tuscarora valley is almost entirely devoid of exposures, but the same rocks occur there as have been already described further west between Waterloo and Peru mills.

Lack township, agriculturally, is largely given up to wheat and some little corn, but the greater portion of its area is still well timbered. The chestnut oak which once grew so thick along the interior slate ridges has been largely cut out for its bark, and a thick but small second growth Chestnut has taken its place.