The Shale - Slate Region, also known as the Slate Belt, is located at the northern half of the Lehigh Valley, bordered by the Blue Mountain Range.

The area is relatively flat with some rolling hills and stream divides. The elevation range is between 500 - 800 feet above sea level.

The main types of rocks include sedimentary rocks (shale and sandstone) and metamorphic rocks (slate). This area is known as the Martinsburg Shale/Slate Formation.

Lehigh Valley was producing about 50 percent of slate in the United States at one time! Slate is a type of fine-grained metamorphic rock that was created through the extreme conditions of pressure and heat (in this case, mountain building events). Around 1800 the slate industryemerged and continued for over 100 years in the Lehigh Valley . After WWII, synthetic materials drastically cut into the demand for slate for such things as chalkboards and pool table tops.