KEEFER SANDSTONE

Site Location: 

Deneen Road, mileage 133.0

          Nearest Access: Lock 54, mileage 134.0

  This white,fine grained, well sorted quartz sandstone represents a significant interruption in the depositional environment that caused the formation of the red siltstone and sandstone sequence of middle Silurian time.  The Keefer resembles the Tuscarora but is thinner and not as indurated with silica; it is a truer sandstone than a quartzite.  This site is the best exposure of the Keefer along the Canal, but it can also be observed just off the Canal, for example, along Deneen Road in road cuts at Cohill Station near mileage 130.5. The Keefer contains Skolithos worm burrows that are perpendicular to the bedding of the sandstone.  That would indicate that the worms were burrowing through the sediments in a vertical direction rather than horizontally.  The fossil evidence supports a marine environment, the physical character of the rock indicates a beach, a beautiful white beach.

  The Keefer at Mile Marker 133 occurs in an anticlinal fold that is worth the visit in itself.  There is also a fine view across the river of the Cacapon Mountain ridge that is capped by the Tuscarora.  The folding of the Keefer here demonstrates its mechanical competence to bend, not break, although minor fractures can be observed.  The Keefer contributes to a complex fold train, called the ‘fluted rocks’, that is exposed along the Cacapon River in West Virginia near where it enters the Potomac on a nearly direct north course opposite mileage 133.55. 

Top of Page