Abstract

The Spitzenberg conglomerate caps the conical hill of that name near Greenawald on the Hamburg, Pennsylvania, topographic map. No other outcrop of similar rock has been found in the surrounding region. Although actual contacts are buried, it seems that the conglomerate rests unconformably upon the Martinsburg shales, the conglomerate being in the form of a gently dipping spoon-shaped syncline, whereas the underlying Martinsburg is highly folded and has steep dips in all adjacent outcrops. The lithology of the conglomerate is variable. Beds of arkosic sandstone, shale, and conglomerate are found, cross-bedding is common, most beds are gray, but some are reddish. The lithology is very similar to that of the Triassic fanglomerates of the Delaware Valley. No fossils have been found in the matrix or pebbles. The pebbles have been studied in an effort to determine their sources. While the Martinsburg and older formations seem to be lithologically incapable of furnishing the pebbles, numerous younger formations could have provided them. The location of the Spitzenberg in relation to the outcrops of these younger formations would require drainage from the north or west to bring the pebbles to their present location. Drainage in this direction is not believed to have existed in the Paleozoic, but it did exist in the Mesozoic. The fanglomerate type of lithology is common in the Triassic, but unknown in the Paleozoic of this part of the country. Although no paleontologic proof is available the Triassic age seems to be the most likely. If the Spitzenberg conglomerate is a Triassic outlier it becomes highly significant in the discussion of Triassic sedimentation in Pennsylvania.

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