Devils Eyebrow

Devil's Eyebrow, a geologic anticline
Devils Eyebrow

NPS /  Nanette Nyce

STRIKING A BALANCE: Resource Use and Preservation

Located a few miles upriver from Hancock, Maryland - Devils Eyebrow (MM 127.24) is easily visible across the canal bed from the towpath. About 480 million years ago, this area was covered by a shallow sea. Over time, various types of sediment settled to the sea bottom.

These layers were bent during the tectonic forces that created the Appalachian mountains. The upper portion of the “Eyebrow” (an example of an anticline) is made of a harder sandstone layers. The lower portion (now hollowed out) was composed of a softer calcium rich limestone layer, which eroded more quickly when the face was exposed to the elements. Mining for limestone also enlarged the hollow portion beneath the upper layer.

Just half a mile upriver from the Eyebrow are the remains of the Round Top Cement Mill. While scouting the potential path for the canal, high-calcium limestone deposits were discovered, and the construction of the mill began in 1838. Due to the intensity of its fires, the mill burned down several times. The tall smokestack still visible from the towpath dates from the third rebuild. Coal to fire the cooking kilns came from up the canal. Five tunnels were bored into Roundtop and several are still visible today from the Western Maryland Rail Trail that parallels the towpath from Big Pool (MM 113) to Little Orleans (MM 141).

Discussion Question: Our landscape is changed by both natural and human forces. How do we find a balance between utilizing and conserving natural resources?

Close up of Devil's Eyebrow
Close up of Devils Eyebrow

NPS / Nanette Nyce

Additional C&O Geology pages: Locks 15-20 | Olmsted Island | Flooding | Purplehorse Beach | Pothole Alley | Widewater | Lamprophyre Dikes | Mather Gorge | Paw Paw Tunnel | Cumberland Coal

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Geologic cross-section of area surrounding Devil's Eyebrow
Sketch of the Devils Eyebrow and ruins of Round Top Cement Company mill west of Hancock, Maryland

Figure 112 from USGS Professional Paper 1691

Last updated: September 6, 2023

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