South Mountain is the southern boundary of the Lehigh Valley. It is not straight and even-ridged like the Blue Mountains, but rather quite the opposite. South Mountain is also known as the Durham Hills, Reading Hills, and the Lehigh Mountains.

The elevation in the South Mountain region is between 500 and 1,000 feet above sea level. Its age range is quite old (Precambrian), ranging from about 570 - 1,600 million years old, although specific ages are not known for sure.

Metamorphic rocks are most common in this area, specifically Gneiss.

Some formations in this region are the Pochuch Gneiss Formation and the Reading Prong Formation.

Left: View of South Mountain from Goodman Campus, Lehigh University Right: View from lookout point on Mountain Dr, Lehigh University

 

Pennsylvania Geology | Geologic Time Scale | What is Geology? | Exploring the Lehigh Valley | Rock-on! Educational Material