The two series or formations whose floras form the subject of this paper are the Allegheny and the Kanawha series. The first, which is typically developed in the Allegheny valley in western Pennsylvania, comprises what has generally been known as the “Lower Productive Coal Measures” in the northern bituminous fields. It lies between the Homewood sandstone, the upper member of the Pottsville formation, and the Mahoning sandstone, a massive sandstone which forms the lower member of the Conemaugh series or “Lower Barren Measures,” consisting in part of red shales. The thickness of the Allegheny series in western Pennsylvania and northern West Virginia is usually about 300 feet.
The Kanawha series is typically exposed along the Great Kanawha river in southern West Virginia. Like the Allegheny series, this series, which will be more fully described on a later page, lies, generally speaking, between a sandstone group, including red shales, above . . .