Page:Report on the geology of the four counties, Union, Snyder, Mifflin and Juniata (IA reportongeologyo00dinv).pdf/401

Rh Suloff’s, nearly all that exposed being shaly and thinbedded.

In Spruce Hill township the Tuscarora synclinal passes nearly midway between the two limestone and chert ridges, flanking it north and south, and as the basin gradually deepens going west these two ridges begin to diverge from each other in the vicinity of Pleasant View, until along the Tuscarora township line the slate valley is 1½ miles wide and shows a much more gentle synclinal than in the narrow trough between Pleasant View and the Juniata river.

The Ore sandstone in this township makes a high terrace on the flank of Tuscarora mountain until within 2 miles of the Tuscarora line, where the terrace ridge seems to end rather abruptly and becomes merged in the main mountain.

The Bloomsburg red shales make a thin band north of the terrace ridge near its base, and are likewise exposed on the crest of the small subordinate axis lying between the South Limestone ridge and the Sink Hole valley synclinal, to within one-half mile of the western township line of Spruce Hill, where they sink out of sight with the axis beneath a wide plain of the upper Salina rocks in Tuscarora township. These red shales are well seen entering from Turbett township near the cemetery and extending to Mrs. Wharton’s house, where the anticlinal shows dips of 50° N. and 45° S.

The village of Spruce Hill is situated on the upper Salina rocks, which, as already stated, form a broad synclinal basin in this township along the line of the Sink Hole synclinal. There is an exposure of these lime shales southwest of Spruce Hill P.O. at the old mill near Guilford’s dipping S. S. 35°, and another further west near Graham’s Mill dipping 45° N. W. showing some red shale.

The Lewistown limestone enters this township on the east just north of the B. S. S., and has been slightly quarried near the junction of the first road to Spruce Hill, upon a 50° N. W. dip. North of J. Ard’s, where Tuscarora creek