Sideling Hill and Town Hill Mountains
Rainwater enters the outcropping sandstones of Sideling Hill and collects in what is termed an aquifer. In this highway cut, the water runs out at the bottom of the fractured sandstone layers because it cannot go through the dense claystone below. There are often continual water seeps or ice falls during winter in a cut like this.
The ridge to the west is Town Hill, a syncline like Sideling Hill. What looks like an end to the hill is a cut, eroded by a river which might have been bigger than today’s Potomac River. Town Hill extends tens of miles into Pennsylvania.
Marker is on the westbound Sideling Hill Visitors Center (Interstate 68 at milepost 75) west of Exit 77 (Maryland Route 144), on the right when traveling west.
Courtesy hmdb.org
