Mole Hill (Virginia)

[1] Mole Hill is an isolated, rounded, tree-covered monadnock in an otherwise relatively flat valley, surrounded by farmland.

[2] The basalt outcropping at the crest of the hill is "dark greenish gray to grayish black, medium grained, and moderately porphyritic.

It is an olivine-spinel basalt with abundant large pale green pyroxene and minor yellow-brown olivine phenocrysts.

[1] In 1969, Fullagar and Bottino used K-Ar and Rb-Sr radiometric dating techniques to date rocks that they thought were temporally related to the Devonian Tioga Bentonite, but discovered that the rocks were actually a much younger age of approximately 47 million years, placing them in the Eocene.

[4] Trimble Knob, located in Highland County, is geologically similar to Mole Hill and thought to be contemporaneous with it, along with other intrusive igneous rocks near Ugly Mountain in Pendleton County, West Virginia.