Figure 7. Tentative, conceptual cross section of study area showing the Ordovician Potomac River fan structure of Drake (1989). The data discussed in this study indicate that the Potomac River fan structure is a composite of foliations formed throughout the Paleozoic. Approximate locations of field stops are indicated. MF, Martic fault; PGF, Pleasant Grove fault; PIF, Plummers Island fault; RCF, Rock Creek fault. |