Page:Report on the geology of the four counties, Union, Snyder, Mifflin and Juniata (IA reportongeologyo00dinv).pdf/35

Rh Union, giving access from the south to the beautiful Kishacoquillas valley.

This equally remarkable valley, composed of an undulating floor of Lower Silurian limestone, and flanked on either side by the Hudson River slates No. III, hemmed in by Standing Stone, Long and Paddy’s mountains on the north and Jack’s mountain on the south, is about 30 miles long and 4 miles wide at its widest part in Mifflin county; but its western extremity, about 5 miles long, is in Huntingdon county, giving about 25 miles to Mifflin county. Like the mountain enclosing it, it is not straight, but curves southwest in a crescent shape, with the bow or apex of the curve pointing northwards.

At its eastern end it is sub-divided by the spurs already mentioned into three separate and narrow valleys: Havise valley on the north, Triester valley in the center and New Lancaster valley on the south, each having its own anticlinal axis.

Standing Stone mountain, the main northern boundary wall of the main valley west of Milroy, terminates eastward in a synclinal spur known as Straley’s or Baird’s Knob, immediately in line with Strong’s Knob, forming part of the Broad mountain range. Further east Long or Paddy mountain bounds the valley. on the north.

Buffalo valley, in Union county, is similarly modified by a series of anticlinal and synclinal flexures, none of which, however, have any special names. The anticlinal mountain prongs of the Buffalo mountains, coming in from Centre and Mifflin counties, narrow the valley considerably along the northwest county line.

Geologically the deepest part of the valley lies just north of Lewisburg, where, as the map will show, there is a canoe-shaped trough of the Marcellus and Hamilton shales and slates, encircled by the Oriskany and Lower Helderberg limestone.

Two other detached areas of these latter groups are shown on the Union county map south of Mifflinburg; but the greater part of Buffalo valley is composed of the Salina marls and shales and the Clinton rocks, spreading out over