Radford University, Catawba Mountain

Friday night I presented a lecture for the Museum of the Earth Sciences at Radford University, where I’m an adjunct faculty member. The museum packs an amazing amount of material into a small space, including the cast Tyrannosaurus skull shown above. In addition to numerous fossils, they also have a large and impressive collection of minerals on exhibit. They are well worth a visit if you’re in the Radford area.***

My Radford class had a field trip scheduled for today, to see lower Paleozoic rocks near Salem, Virginia. The highway between Hanging Rock and Catawba cuts through the Salem Syncline. Just above Hanging Rock are exposures of the Devonian Millboro Shale, such as the one below:

The road winds its way up to the top of Catawba Mountain, where it’s crossed by the Appalachian Trail. Near the trailhead is the boundary between the Silurian and Ordovician rocks.

On the right is the Silurian “Keefer” Sandstone, which was deposited near the shore. On the left is the older Ordovician Martinsburg Shale, which was deposited in deeper water. The Silurian sandstones are resistant to erosion, and form the summit of Catawba Mountain. The softer shales in the Devonian and Ordovician are eroded on each side.

A little further down the mountain there is a large exposure of the Martinsburg that contains a fair number of fossils. Most of these are tiny articulate brachiopods like the ones below:

There are also a fair number of inarticulate brachiopods, like this one:

Besides brachiopods, various mollusks have been found here, including bivalves and snails, as well as trilobites. The Martinsburg is Late Ordovician in age, so these animals lived about 450 million years ago.