Nittany Valley is the intermountain region of Centre and Huntingdon counties, lying between Tussey Mountain and Bald Eagle Mountain and drained by Spruce, Spring and Little Fishing creeks. It is significant because of its underlying geology of the Gatesburg and limestone bedrock formations.
Coming Together at the Center
Nittany Valley lies precisely at the geographic center of Pennsylvania, between two long mountain ridges: Bald Eagle Mountain and Tussey Mountain. Biodiversity significance is particularly important within the intermountain lowlands of this region. Here, the bedrock geology is composed of multiple limestones and the rare gravelly Gatesburg Formation.
One of the most unique landscapes in the state, this valley includes: a mixture of pitch-pine scrub oak sand barrens dotted with vernal pools; the Spring Creek valley with its alkaline soils, limestone cliffs and rich vegetation; and karst (cave permeated) valleys underlain with limestone aquifers, sinkholes and solutional caves. The outflows from groundwater reserves form some of the largest natural springs in the region and are the source for high-quality streams such as the cold and clear Spruce Creek. These unusual ecosystems harbor rare species, such as Stellmack’s cave amphipod and Franz’s cave isopod, crustaceans known to exist in few other places on Earth.
Large, intact forests exist on the adjacent mountains, but lower limestone soil-based forests are essentially not present due to a high degree of fragmentation related to agriculture, highways and expanding development. The conservation of biodiversity in Nittany Valley brings its own set of particular challenges to protecting and restoring its signature life forms and ecosystems. One particular challenge will be to assure viability by restoring lowland forests in certain areas to larger sized patches and to create corridors for wildlife. Protecting groundwater quality and reducing fragmentation are other conservation goals.
- Spring Creek valley: ecologically diverse forests with limestone slopes and cliffs
- The Barrens: pitch-pine scrub oak barrens and numerous vernal pools
- Spruce Creek: karst (cave permeated) valley, springs and a subterranean ecosystem
- Little Fishing Creek
- Six important ecosystems: vernal pools, caves, limestone springs, limestone cliffs, barrens, alkaline creeks, pitch pine-scrub oak barrens and low elevation forests.
- 30 occurrences of globally rare plants, invertebrates and vertebrates including the northern metalmark butterfly and the golden-winged warbler.
- Seven Biological Diversity Areas totaling 10,000 acres and harboring species and ecosystems above
- 45 miles of important stream ecosystems
This bedrock layer was formed during Earth's Cambrian Period, which means that rocks exposed at its surface are some of the oldest rocks that can be found in the state. The Gatesburg consists of sublayers of sandstones, limestones and dolomites (limestone with magnesium). Because of its sand, gravel and limestone content, the Gatesburg’s subsoils are coarse and very well drained, yet include some calcium content. Iron deposits in the Gatesburg drew steel magnate Andrew Carnegie to mine certain areas here in the 1880s.