REMARKS: An outcrop of the Tuscarora quartzite (Silurian age) forms the highest observation point in Lehigh County, 1600 feet above sea level. The knob rises about 50 feet above the even crest of Blue Mountain and affords a view southward over the Lehigh Valley and northward over a series of ridges and valleys in Carbon and Schuylkill Counties. The knob was named after a peculiar bowl-shaped topographic feature that resembles an old-fashioned bake oven. The Appalachian Trail, extending from Maine to Georgia, passes near Bake Oven Knob.
REFERENCES: Berlin, A. F. [1922], The Bake Oven Knob, Lehigh County Historical Society, Proceedings 1922, p. 44-48.
Miller, B. L., Fraser, D. M., Miller, R. L., and others [1941], Lehigh County, Pennsylvania, Pennsylvania Geological Survey, 4th ser., County Report 39, 492 p.
REMARKS: A mass of dark- and light-banded Pochuck gneiss (Precambrian age) rising about 40 feet above the ridge line; its top is about 1040 feet above sea level. A panoramic view of Saucon Valley to the north can be seen from the crest. The pinnacle is due to the fact that there are fewer joints and cracks in the gneiss at Bauer Rock than the surrounding rock formations; Bauer Rock has not eroded away as quickly as the rest of the mountain because the presence of fewer joints impedes the weathering process on the gneiss.
REFERENCES: Miller, B. L., Fraser, D. M., Miller, R. L., and others [1941], Lehigh County, Pennsylvania, Pennsylvania Geological Survey, 4th ser., County Report 39, 492 p.
REMARKS: An outcrop of the Tuscarora quartzite (Silurian age) forms three large blocks standing in a row; is said to have housed many bears.
The Tuscarora Formation underlies Blue Mountain and is the hardest rock found in the region and the most resistant to erosion. this accounts for the relatively great height of Blue Mountain compared with the Great Valley. The Tuscarora quartzite is composed of rounded quartz grains firmly cemented by silica.
REFERENCES: Berlin, A. F. [1922], The Bake Oven Knob, Lehigh County Historical Society, Proceedings 1922, p. 44-48.
Miller, B. L., Fraser, D. M., Miller, R. L., and others [1941], Lehigh County, Pennsylvania, Pennsylvania Geological Survey, 4th ser., County Report 39, 492 p.
REMARKS: The jasper is in the Hardyston Formation (Cambrian age) and is exposed in massive beds forming low cliffs. This is the only known locality in Pennsylvania that has this form of occurrence; it is geologically notable. The jasper is coarse and all traces of bedding planes have been obliterated. Vein quartz is scattered sparsely through the rock, and there are numerous tension cracks and some cavities; these characteristics are very uncommon in jasper outcrops.
REFERENCES: Miller, B. L., Fraser, D. M., Miller, R. L., and others [1941], Lehigh County, Pennsylvania, Pennsylvania Geological Survey, 4th ser., County Report 39, 492 p.
REMARKS: A magnificent water gap in Blue Mountain. Erosion by the Lehigh River over millions of years brought the gap to its present elevation. A nearly continuous rock sequence from the top of the Martinsburg Formation (Ordovician age) to the Middle Silurian can be seen along the east bank of the river; it is the "type section" of the Lizard Creek Member of the Shawangunk Formation (Lower Silurian).
REMARKS: High-quality jasper was discovered here by the Delaware Indians. At the height of activity, more than 100 small pits or quarries were operated. The light-brown jasper from these quarries found its way up and down the eastern seaboard, from New England to Georgia. The quarries were abandoned around 1680.
REFERENCES: Miller, B. L., Fraser, D. M., Miller, R. L., and others [1941], Lehigh County, Pennsylvania, Pennsylvania Geological Survey, 4th ser., County Report 39, 492 p.
Geyer, A. R., and Lapham, D. M. [1970], Pennsylvania's first mineral industry - Indian jasper quarries, Pennsylvania Geology, v. 1, no. 6, p. 11-12.