The Centre-Franklin township line at the head of the ravine near J. Shambach’s place closely limits the southern outcrop of the Catskill rocks.
From Centerville to Beavertown, through the “Ridges,” there are but few exposures of value, the Devonian rocks being very shaly and their low dips create a very uniform erosion.
14. Adams Township in Snyder county.
This township lies immediately west of Centre and like it has the Jack’s mountain crest for its northern line nearly 6 miles in length, now a perfectly straight line extending for nearly 4 miles along the central Oneida mountain and the balance eastward in the Medina red sandstone No. IVb. Its east and west border lines are of nearly equal length, the former, 3 miles long, being straight and the latter, about 3½ miles long, with three or four angles. The southern line, with one obtuse angle, fairly continues the Centre township line westward, and is about 4 miles long, so that the area will approximate 12 square miles. This is a new township, created entirely out of Beaver township.
Troxelville and Port Ann are two small villages situated on either side of Kline ridge, which is a low limestone hill running east and west through the center of the township.
All the drainage is southward into Middle creek, the right hand fork of which heads up in Centre township and receives three or four small mountain branches in Adams township before it turns south to cut across the Northumberland synclinal to join the main Middle creek in Beaver township.
The structure here is quite similar to that of Centre township although it receives one important modification in the presence of the Swift Run synclinal, which, further west, cuts off a portion of Jack’s mountain and continues westward into Mifflin county as the Beatty’s Knob synclinal between the Triester and New Lancaster anticlinals of the Kishacoquillas valley. In Adams township its effect is very slight, merely causing a slight offset in the Bloomsburg red shales along the Spring township line.
