Page:Report on the geology of the four counties, Union, Snyder, Mifflin and Juniata (IA reportongeologyo00dinv).pdf/73

Rh to a more limited extent along the river in Chapman township north of Port Treverton.

The Catskill rocks nowhere furnish minerals or substances of economical value. The country occupied by them is ragged and considerably cut up by small and narrow ravines, eroded out of the softer shaly members. It furnishes a fairly good soil where cleared, but it is not largely farmed in Snyder county.

The next underlying group of rocks is designated collectively as No. VIII on the map, and is colored brown. No attempt was made to differentiate the formation into its several members, Chemung, Portage, Genesee, Hamilton and Marcellus: for in places the rocks of some one division cannot be recognized at all, and with the exception of the Marcellus, which carries a limestone and a bed of carbonate ore at its base, and the two lower Selinsgrove limestone beds in Snyder county, no valuable mineral deposit has been found in them.

Along the Susquehanna in Snyder county the Chemung and Portage cannot be separated, mainly owing to the absence of the flaggy structure of the Portage, which characterizes this formation along the Juniata and the Pennsylvania railroad cuts between Newton Hamilton and Mt. Union, in Mifflin county.

The Chemung and Portage rocks combined (VIII g, f,) can be fairly well distinguished through Snyder county from the underlying Genessee and Hamilton by their lithological character and different type of topography they make. The former here consists of a top series of green, gray and olive shales, with some few thin splintery sandstones, grading downwards into harder sandstone beds, dark gray and brown, with very little slate, weathering into irregular but small fragments, which ring like a bell when struck, and are very splintery.

The whole double group, 2500′ thick, contains many fossil