Page:Report on the geology of the four counties, Union, Snyder, Mifflin and Juniata (IA reportongeologyo00dinv).pdf/278

250 F³. and west, and 5 miles in breadth north and south, with an area of about 30 square miles.

Lewistown, the county seat of Mifflin county, although having its individual borough lines, is essentially a part of this township; whilst Logan on the Kishacoquillas creek and the Milroy Branch R. R., with it important iron and steel industries, makes another center of population. Yeagertown, located on the pike immediately north of Logan, is strung out for nearly a mile towards the Logan gap, and is largely occupied by the employés of the Logan Co. and Mann’s Axe Faetory. Maitland Station on the Lewistown and Sunbury R. R. about 5 mile east of Lewistown is a village in the southeast corner of the township.

The Kishacoquillas creek flows in a southerly direction across the western end of the township from Logan gap to the Juniata river at Lewistown. A mile still further down the river Jack's creek enters, flowing westward from Decatur township along the railroad for 3 miles before cutting across the Clinton foot hills to the north base of Shade mountain.

The Logan and Lewistown sections, Report F, plates 7 and 8, were constructed in 1874, by Mr. J. H. Dewees and his assistants. Both these sections are illustrated in that report and both show two double synclinal ridges of Oriskany sandstone and shale, one known as the Prospect Rock basin; the other and more northern, as the Dry Valley basin. Both these synclinals hold small portions of the lower No. VIII or Marcellus rocks, whilst the anticlinal valley between them is occupied by the Lewistown or Lower Helderberg limestone No. VI.

North of the Dry Valley basin along the Kishacoquillas creek, there is an anticlinal of the Salina rocks, which, increasing in strength westward; brings to daylight in Granville township the underlying ore sandstone; and eastward, in Decatur township, passes through the most northern of the two anticlinal loops there, but so far decreased in strength as to be saddled only with the upper Salina marls and the Lewistown limestone.

Between this axis and Jack’s mountain there is a regular