Latitude:                         40° 30' 07"N

Longitude:                      79° 56' 37"W

Quadrangle:                    Glenshaw 7 1/2'

Age:                                Pennsylvanian

Formation(s):                  Conemaugh Group, Glenshaw Fm., channel sandstone just above the WoodsRun limestone.

Purpose:                          This site provides easy access to a compact sandstone channel.

When you arrive at this site, pull up to the wide berm near the large green highway sign giving directions to Butler, Etna, and Kitanning St. Parking available for motor coach. If you pass this parking area, YOU CANNOT TURN AROUND. Site is easy to access with a short walk along the highway ramp. NOT recommended for children. Traffic is very fast and dangerous in this area.

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

From Oakland, take any bus to downtown Pittsburgh. Then 1B, 1C, 1D, or 3D to Etna. Get off in Etna at closest stop to Rt. 28 and walk back (against traffic) along northbound ramp from Rt. 28 to Rt. 8. Outcrop is along exit ramp as described above. Return.

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. Go approximately 6.6 miles and take the exit for Rt. 8 North (Etna). Stop near end of exit ramp as described above.

See map and figures.

Here is a well exposed sandstone channel in the lower portion of the Glenshaw Formation. The channel contain some good examples of cross-bedding and a sharp erosional base.

Geologic History: Environment of Deposition:

The Glenshaw Formation represents the lower delta plain or distributary environment that extends into a regional basin that is being filled from the rising Appalachian mountains to the southeast (today's direction) and from highlands to the north (today's direction). The channels were formed by streams that cut across and through pre-existing delta deposits as they prograded out into the basin. 

Click on the thumbnails below for pictures of the outcrops:

Sandstone channel in the Glenshaw Formation showing a sharp erosional base.

Continuation of the above photo toward the North.

Further continuation of the above photo toward the North.

Close-up of the base of the cross-bedded sandstone channel and erosional contact with underlying shales.

Another shot of the cross-bedding

No fossils found.

Berryhill, H. L., Jr., Schweinfurth, S. P., and Kent, B. H., 1971, Coal-bearing Upper Pennsylvanian and Lower Permian Rocks, Washington area, Pennsylvania: U. S. Geological Survey Professional Paper 621, 47p.

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 pages.

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.

Shaw, E. W., and Munn, M. J., 1911, Geologic Atlas of the United States: Burgettstown-Carnegie Folio, United States Geological Survey Folio 177 Field Edition, 123p.

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)