Page:Report on the geology of the four counties, Union, Snyder, Mifflin and Juniata (IA reportongeologyo00dinv).pdf/223

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21.Washington Township in Snyder.

F³. 195

seven-eighths of the township through branch streams flow- ing eastward.

A small triangular area at the extreme south corner and a little territory near the base of Shade monntainalong the Perry township line, are drained by upper branches of Mahantango creek. The structure is extremely simple and very regular, all the rocks dipping sontheastward from the northern end of the township away from the Shade mount- ain or Selingsgrove anticlinal, whose axial line passes in a northeast and southwest direction close to its northern border and crosses Middle creek just below Kantz’s mill. To the north of this line there are few north dips, but ex- ceedingly gentle, as the axisisa very broad and regular one.

The Shamokin synclinal occupies the high ground in the triangular-shaped area on the south, but the Devonian measures held in the basin there are not well exposed, so that the exact, position of the axis can not be well deter- mined.

Freeburg, nearly in the center of the township, is the only place of importance, and is situated in a fertile valley of upper Salina shales upon the north bank of a good-sized tributary of Middle creek, skirting the north base of the Firestone ridge.

The rock series in this township extend from the top of the white Medina sandstone No, [Vc up to and includivg the Chemung division of No. VIII, the former being ex- posed slightly in the nose of Shade mountain at the mutual corner of Washington, Franklin and Perry townships.

The lower Clinton rocks, between the Medina sandstone and the Ore sandstone, are excellently exposed all through the northern portion of this township on the crest of the south flank of the Shade mountain axis; and at one time the purity of the Bird Hye fossil ore bed, as well as the many advantageous circumstances attending its flat dip, led toa very large development of this bed in nearly every little branch which cnt down beneath its outcrop. Many of these.openings were visited when active by Mr. J. H. Dewees, and a description of them, with analyses of the

ore then being mined (1874), will be found in Report F, p. 26, et seq.