Geology
The Bull Run Mountains are a geological extension of the same formation that makes up the Catoctin Mountain. This formation consist mainly of Catoctin greenstone interspersed with white quartz and Precambrian metamorphosed basalt flows. The lower ridges on the eastern front also contain Jurassic basalt flows. These rocks were transported westward to their current location and uplifted during the Alleghenian Orogeny.
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