Page:Report on the geology of the four counties, Union, Snyder, Mifflin and Juniata (IA reportongeologyo00dinv).pdf/345

Rh of the synclinal dipping 20° southeast, making a valley through which Dobson’s run flows, flanked north and south by high ridges of Hamilton sandstone. The latter rocks are fairly well exposed at the head of Dobson’s run, near the Perry county line and its junction with Susquehanna and Greenwood townships, dipping there about 40° northwest. This ridge therefore is everywhere a monoclinal, except near the river, where the south leg of the Tuscarora anticlinal forming the Wild Cat ridge of Perry county laps around the head of Pfoutz’s valley to make, with Turkey ridge, a single hill of Hamilton and Chemung rocks dividing Juniata and Perry counties.

The Turkey valley in Greenwood township is equally devoid of satisfactory exposures; but in a general way Crane’s run emptying into Cocolamus creek at the Perry county line in the southwestern corner of the township flows westward through the same Genessee slate valley occupied by Dobson’s run east of the little summit dividing these two streams. About a mile southeast of the Seven Stars Hotel the brown and black Genessee shales, along Crane’s run dip but 15° to the northwest, and continue on that dip almost to the hotel, the road running diagonally across the measures. Northwest of the Seven Stars there is a belt of the lower Hamilton shales with a conformable dip, which continues until after passing McDaniel’s place where the bottom layers of the Chemung gray and brown sandy slates and thin sandstones dip but 5° to the northwest along Little Cocolamus creek within one-half mile of the Monroe township line.

Above the saw mill, in this township, after passing over a narrow strip of red shales along the township line, brown shale and sandstone, evidently of Chemung age, show with an increased northwest dip of 15°; but in the next one-fourth mile and near the forks of the creek, this dip is reversed in the same measures to one of 40° southeast and 30° just below the school-house. The main synclinal axis therefore of the Tuscarora valley can be definitely located at the forks of the creek near the Monroe-Greenwood township line. Still further north, along Little Cocolamus creek,