Pound Gap

 

Once you locate the long ridge of Pine Mountain on the horizon (see its placeholder in the guide), follow that ridge to the west, or left, all the way to where it disappears out of view below the treeline of a ridge between Pine Mountain and the Knob. If the sky is clear enough, you might be able to make out a sharp dip, or "cut" in Pine Mountain at this spot or even see an open rock face in this dip, if you have binoculars.

 

This gap in the mountain is known as Pound Gap, a low spot in the 

 

 

 

 

 

 

ridge through which U.S. Highway 23 travels on its way into Kentucky. Pound Gap is famous for a number of historical and cultural reasons, most related to the fact that the gap forms one of the only easily-traveled routes over Pine Mountain along its 100+ mile-long extent. 

 

The same rock cut that allows four-lane U.S. 23 to pass through the gap, however, has exposed one of Pine Mountain's most incredible natural features. As mentioned in the Pine Mountain placeholder, the long ridge of Pine Mountain is actually the lip of a massive block of rock that was thrust up and over rocks to the north during the Appalachians' last orogeny, or mountain-building event. The force of this event took layer upon layer of sedimentary rock - or rocks that were produced from layered sediment when our portion of the Appalachians was submerged beneath an ancient, inland sea - and slanted them up and over the rocks found to the north in modern-day Kentucky. Normally, this history is completely hidden belowground, with only the sharp, north-facing cliffs on Pine Mountain's crest serving as evidence of this 300 million year-old geologic history.

 

In Pound Gap, however, that history has been laid out for us to see. The rock cut that carries U.S. 23 through the gap exposed these "thrust-faulted" layers of rock, which all slant sharply to the north, away from Virginia into Kentucky. Although these layers cannot be seen from the Knob, they are easily seen from U.S. 23 as it continues into Kentucky and forms yet another example of the amazing, complex history of the region that we mostly see as stable today.