REMARKS: The topographic crest of the Laurel Hill and the gelogical structural axis of the Laurel Hill anticline. Sandstone outcrops of the Allegheny Group (Pennsylvanian age) are exposed through weathering; there is a scenic view from the rim of the mountain. The name was applied to this feature because forest growth was slow to develop on this dry, rocky site. Strange sounds, similar to a swarm of bees, are peculiar to this knob; these sounds are attributed to traffic on the Pennsylvania Turnpike, located about 0.8 mile to the south.
REMARKS: Hard, resistant sandstone of the Connequenessing Formation (Pottsville Group, Pennsylvanian age) caps the elongated knobs on the crest of Chestnut Ridge; approximately 2 acres of weathered sandstone crops out. Joints in the sandstone that have been enlarged by weathering form a miniature "rock city"; very scenic.
REFERENCES: Shaffner, M. N. [1958], Geology and mineral resources of the New Florence quadrangle, Pennsylvania, Pennsylvania Geological Survey, 4th ser., Atlas 57, 165 p.
REMARKS: The Conemaugh River has eroded flat-lying sandstones, siltstones, and shales to form a magnificent gorge several miles in length. The topographic crest of the gorge (Laurel Hill) corresponds almost exactly in position to the Laurel Hill anticlinal axis. Massive sandstones of the Pottsville Group (Pennsylvanian age) form the rim, whereas softer, sandy shales of the Oswayo Formation (Devonian age) are exposed at the base. The geologic record of hundreds of millions of years is recorded in the rocks at this site.
Where the crest of the ridge is formed by the massive and resistant sandstones of the Pottsville Group, the land is forested and relatively unpopulated. Laurel Hill is an excellent example of the influence of the rocks on man's activities; the ridge is covered with massive sandstone boulders and is practically uninhabited.
REFERENCES: Phalen, W. C. [1910], Johnstown, PA, U. S. Geological Survey Atlas, Folio 174, 16 p.
REMARKS: An extremely scenic water gap eroded by the Conemaugh River through Chestnut Ridge; the topographic crest of the Chestnut Ridge coincides with the axis of the Chestnut Ridge anticline. Massive sandstones of the Pottsville Group (Pennsylvanian age) form the rim, whereas softer, sandy shales of the Oswayo Formation (Devonian age) are exposed at the base. The geologic record of hundreds of millions of years is recorded in the exposed rocks.
REFERENCES: Shaffner, M. N. [1958], Geological and mineral resources of the New Florence quadrangle, Pennsylvania, Pennsylvania Geological Survey, 4th ser., Atlas 57, 165 p.
REMARKS: A 3-mile-long gorge cut by Loyalhanna Creek through Chestnut Ridge; elevations range from 1040 feet at stream level to above 1900 feet on the rim. The river gradient drops about 100 feet in 3 miles and there are sections of boulder-stream rapids (Buttermilk Falls (128) is the largest and most spectacular).
The topographic crest of the gorge (Chestnut Ridge) corresponds almost exactly in position to the axis of the Chestnut Ridge anticline. Massive sandstones of the Pottsville Group (Pennsylvanian age) form the rim, whereas softer, sandy shales of the Oswayo Formation (Devonian age) are exposed at the base. The geologic record of hundreds of millions of years is recorded in the rocks of this gorge.
REFERENCES: Campbell, M. R. [1904], Latrobe, PA, U. S. Geological Survey Atlas, Folio 110, 15 p.
TOWNSHIP: CookREMARKS: Outcrops of sandstone of the Allegheny Group (Pennsylvanian age) form a cliff at this site; the view of Linn Run gorge and the Ligonier highlands is excellent. Nearby in the gorge, Adams Falls (131), Grove Run Spring (132), Flat Rock (133), and Wolf Rocks (134) are notable geologic features. Sandstones of the Pottsville Group (Pennsylvanian age) form Wolf Rocks; examples of joint blocks, frost wedging, and exfoliation are common along the trail to, and at, this site; a scenic overlook similar to that at 90-Foot Rocks is present.
A little more than 2 miles east of Wolf Rocks and about 2000 feet east of Laurel Summit Road, Beam Rocks (135) (Somerset County, Lincoln Township) and vista are very similar to 90-Foot Rocks, geologically and topographically.
PHOTO: © Michael Lane.