| Wills Creek Formation | |
|---|---|
| Stratigraphic range: Silurian | |
 Tight anticlinal fold in the Wills Creek Formation, along Route 22, Neff, Huntingdon County, Pennsylvania | |
| Type | sedimentary |
| Underlies | Tonoloway Formation |
| Overlies | Bloomsburg Formation and Williamsport Formation |
| Lithology | |
| Primary | Sandstone, shale |
| Other | Siltstone, limestone, dolomite |
| Location | |
| Region | Appalachian Mountains |
| Extent | Pennsylvania, Maryland, Virginia, West Virginia |
| Type section | |
| Named for | Wills Creek at Cumberland, Allegany County, Maryland |
| Named by | P. R. Uhler, 1905[1] |
Wills Creek Formation is a mapped Silurian bedrock unit in Pennsylvania, Maryland, Virginia, and West Virginia.
- ^ Uhler, P.R., 1905, The Niagara period and its associates near Cumberland, Maryland: Maryland Academy of Science Transactions, v. 2, p. 19-26.