| Antietam Formation | |
|---|---|
| Stratigraphic range: Cambrian | |
 Anticline in schist of Antietam Formation | |
| Type | Formation |
| Unit of | Chilhowee Group |
| Underlies | Tomstown Dolomite |
| Overlies | Harpers Formation |
| Thickness | 550 ft |
| Lithology | |
| Primary | Sandstone, quartzite |
| Other | Schist |
| Location | |
| Region | Appalachia, Eastern United States, and Southeastern United States |
| Country | United States |
| Extent | Maryland, Pennsylvania, Virginia, [1] and West Virginia |
| Type section | |
| Named for | Antietam Creek |
The Antietam Formation or Antietam Sandstone is a geologic formation in Pennsylvania, Maryland and West Virginia. [2] [3] [4] It is largely quartz sandstone with some quartzite and quartz schist. It preserves Skolithos trace fossils dating back to the Cambrian Period. [5]
Tight folds in the schist of Antietam Formation
Thin section of schist. Porphyroblastic biotite, a, in a dolomitic matrix. The tourmaline, t, is epigenetic.
