Latitude:                             40° 32' 37"N

Longitude:                          79° 45' 35"W

Quadrangle:                        New Kensington 7 1/2'

Age:                                    Pennsylvanian

Formation(s):                      Conemaugh Group, Glenshaw Formation, Pine Creek Limestone through Woods Run limestone.

Purpose:                              The Pine Creek at this site exhibits some unusual limestone mounds. The entire section between the Pine Creek and Woods Run limestone is exposed here.

Park in back of restaurant. Walk to slope where rocks are exposed. Parking available for motor coach. Recommended for all age groups.

(Make sure you get an up-to-date PAT Transit schedule:

No PAT Transit service.

From the Cathedral of Learning, Drive 0.7 mi. west on Fifth Avenue. Make a Left on Craft Av. Go 0.1 mi., then make a right onto Blvd. of Allies, go 1.6 mi. then bear right onto I-579. Stay on I-579 across the Allegheny River then get onto Rt. 28 East. Stay on Rt. 28 approximately 18.4 miles to the New Kensington Exit. Bear right onto the exit ramp. At end of exit ramp, make a right. Go 500 feet. At T intersection, make a right and go 1.3 miles. Make a left onto the New Kensington Bridge. Go approximately 0.5 miles and make a right onto Constitution Boulevard. Go south 0.8 miles. At the T intersection make a left. Go 1200 feet and make a right. Go south 3500 feet and make a left into the parking lot behind restaurant. Outcrop is on hillside.

See map and figures.

The Following is taken from Donahue and Rollins (1974):

    "The largest of the two mounds is over 10 feet high and consists of a gray limestone cone cut by four truncation surfaces. The highest truncation surface coan be correlated with a similar surface within the inter-mound limestone (i.e, the limestone between the mounds).

    The lithology of the mound limestone is very similar to the inter-mound limestone except for vertical, bifurcating burrows in the center portion of the mound. In thin section the burrows are either filled with fossil fragments, with a micrite, or sometimes spar cement and 20% to 30% clayy and silt size quartz, or a drusy calcite fill with a micrite boundary separating the burrowed and unburrowed limestone. The unburrowed mound limestone, as well as the inter-mound limestone, are both high in clay and silt and contain fossils of crinoids, brachiopods, bryozoans, gastropods, and foraminifera.

    The occurrence of coal below the Pine Creek limestone (to the left of the largest mound) is unusual in the Pittsburgh area and probably represents an isolated peat marsh adjacent to more common delta-margin sands and silty clays of the Buffalo sandstone lithology. In the Pittsburgh area the Pine Creek limestone is usually sa andy, often crinoidal, limestone which is either directly above the Buffalo sandstone or which has a gray calcareous claystone below the limestone and overlying the sandstone. A gray shale occursbelow the Pine Creek limestone here, and within the shale lithology are sand lenses. One such lens, about five feet to the right of the smaller mound contains brachiopods and bivalve shells and fragments of bryozoans. These sandstone lenses probably represent channels in a tidal flat or estuary.

    Above the Pine Creek limestone at this stop, the gray shale also contains fauna very similar to the limestone with the addition of a few conodonts (Streptognathodus and Hindeodella). Within two to three feet of the top of the limestone, the gray shale grades into a tan, nonfossiliferous siltstone. Fifty feet above the Pine Creek marine horizon is the Woods Run limestone. The limestone is sis inches to a foot thick with a mold fauna of molluscs, crinoids, and trilobites."

In the lower part of the sandstone located 36 feet above the Pine Creek limestone common lepidodentron and stigmaria fossils may be found. Also, in the sandstone unit directly above the limestone you may find occasional symmetrical oscillation ripple marks indicating tidal activity.

Geologic History: Environment of Deposition:

See above and Norton (1974).

Stratigraphic section of the Pine Creek and Woods Run marine events

Paleogeographic map showing the region during Pine Creek limestone time.

Paleogeographic map showing the region during Woods Run limestone time.

Click on the thumbnails below for pictures of the outcrops:

Pine Creek limestone.

Pine Creek limestone mound (see above).

Another Pine Creek Limestone mound (see above).

Symmetrical ripple marks in the siltstone above the Pine Creek limestone.

Thin coal below the Pine Creek limestone. It may be found below the abandoned trailer.

Lepidodendron specimen from the siltstones above the Pine Creek limestone.

Stigmaria root from the siltstones above the Pine Creek limestone.

A very good fossil collecting locality. Look for bryazoans and crinoids in the Pine Creek limestone, and plants in the overlying shales and siltstones.

Busch, R. M., and Brezinski, D. K., 1984, Stratigraphic analysis of Carboniferous rocks in southwestern Pennsylvania using a hierarchy of transgressive-regressive units: Field Trip Guidebook for the Eastern Section Meeting of the American Association of Petroleum Geologists. 104 p.

Busch, R. M., and Rollins, H. B., 1984, Correlation of Carboniferous strata using a hierarchy of transgressive-regressive units: Geology, v. 12, p. 471-474.

Brezinski, D. K., 1983, Developmental Model for the Appalachian Basin marine Incursion: Northeastern Geology, v. 5, p. 92-99.

Donahue, J., and Rollins, H. B., 1974, Paleoecolgical anatomy of a Conemaugh (Pennsylvanian) marine events: in Briggs, G., ed., Carboniferous of the Southeastern United States, Geological Society of America Special Paper 148, p. 153-170.

Donahue, J., and Rollins, H. B., 1974, Conemaugh (Glenshaw) Marine Events: Field Guidebook for the third Annual Meeting of the American Association of Petroleum Geologists. 104 p.

Donahue, J., and Rollins, H. B., 1979, Coal Geology of the Northern Appalachians: Field Trip Guidebook for the Ninth International Congress of Carboniferous Stratigraphy and Geology. 45 p.

Edmunds, W. E., Skema, V. W., Flint, N. K., 1999, Pennsylvanian, in Shultz, C. H., ed, The Geology of Pennsylvania, Pennsylvania Geological Survey Special Publication 1, p. 149-169.

Harper, J. A., 1990, Fossil Collecting in the Pittsburgh Area, Pittsburgh Geological Society Guidebook, 50 p.

Johnson, M. E., 1928, Geology and Mineral Resources of the Pittsburgh Quadrangle, Pennsylvania: Pennsylvania Geological Survey Bulletin A 27, 236 p.

Leighton, H. 1945, The Geology of Pittsburgh and its Environs: A Popular Account of the General Geological Features of the Region: Carnegie Institute Press, 2nd edition, Pittsburgh, PA , 80p.

Norton, W. 1974, Biogenic mounds in the Lower Conemaugh (Missourian, Pennsylvanian) of the Appalachian Basin: in Donahue, J., and Rollins, H. B., 1974, Conemaugh (Glenshw) Marine Events: Field Guidebook, 3rd Annual Meeting, Eastern Section, American Association of Petroleum geologists, Pittsburgh Geological Society, p. B-1 - B-6.

Wagner, W. R., and others, 1970, Geology of the Pittsburgh Area: Pennsylvania Geological Survey General Geology Report G 59, 145p.

Click here for  an image of the County Geologic Map (1880)