REMARKS: A boulder field of large angular rocks. The field contains boulders of sandstone and conglomerate of the Shawangunk Formation (Silurian age), and occupies a relatively flat area in the center of a wind gap in Blue Mountain. Shawangunk sandstone from the sides of this gap represents the source for all of the material in the field. During glacial times repeated breakup of the rock by frost action on these nearby ridges resulted in a pile of angular boulders at the base; continued movement during glacial time to where they rest today has caused the boulders to become semirounded.
REFERENCE: Miller, B. L., Frazer, D. M., and Miller, R. L. [1939], Northampton County, Pennsylvania, Pennsylvania Geological Survey, 4th ser., County Report 48, 496 p.
REMARKS: Outcrops of Byram gneiss (Precambrian age); as in Hexenkopf Rock (329) to the south, here is exposed one of the oldest rocks in Pennsylvania and North America. Weathering of the gneiss has produced a topographic figure resembling an elephant.
REMARKS: Outcrops of Pochuck gneiss (Precambrian age); on of the oldest rocks in Pennsylvania and North America. The mineral magnetite is present in the rock.
REFERENCE: Miller, B. L., Frazer, D. M., and Miller, R. L. [1939], Northampton County, Pennsylvania, Pennsylvania Geological Survey, 4th ser., County Report 48, 496 p.
REMARKS: One of the best known and most collected mineral areas in the state; a wide variety of minerals is found. Much of the limestone has been recrystallized into marble; the age of the major period of mineralization is Precambrian.
REFERENCES: Geyer, A. R., Smith, R. C., II, and Barnes, J. H. (1976), Mineral collecting in Pennsylvania, 4th ser., General Geology Report 33, 260 p.
Montgomery, Arthur (1957), Three occurrences of high-thorian uraninite near Easton, Pennsylvania, American Mineralogist, v. 42, p. 804-820.
Montgomery, Arthur (1975), Pennsylvania Minerals (Postscript), Mineralogical Society of Pennsylvania, Keystone Newsletter, v. 24, no. 5, p. 8-9.
——— (1975), Pennsylvania Minerals (Second postscript), Mineralogical Society of Pennsylvania, Keystone Newsletter, v. 24, no. 6, p. 7.
Peck, F. B. (1911), Preliminary report on the talc and serpentine of Northampton County and the portland cement materials of the Lehigh district, Pennsylvania Geological Survey, 3rd ser., Report 5, 65 p.
REMARKS: The best example of a "wind gap" in Pennsylvania. A wind gap is a major "cut" through a ridge through which no river flows.