Fridley Gap Geology Field Trip for Cohort VII

On July 2, 2021, Matt Heller from the Virginia Department of Mines, Minerals and Energy, Division of Geology and Mineral Resources and John Bauman, HMN Field Trips Coordinator, led Cohort VII on a hike to Fridley Gap. After introductions, Matt brought out his cool maps showing the geologic features of the region and described how we’d be walking forward in time as the newer rock formations were further up the trail due to the way layers dipped due to geologic forces.

We’d be traversing four major formations, from 450 million to 400 million years ago. The first formation was the Edinburg formation; “bluestone” limestone. OK, truth be told, this was the gravel in the parking lot, likely deposited from Frazier quarry. Most geologists wouldn’t pass up such a teaching moment I’m sure.

A short way from the parking lot, Matt showed us our first real formation, a bank with exposed shale bedrock, an example of the Martinsburg formation from the late, or Upper, Ordovician period. Only a short way up the trail we encountered our next formation, Massanutten sandstone. This sandstone, a very light gray in color, from the Silurian period was the predominant rock we saw throughout the hike, in outcroppings, talus slopes and trail steps & obstacles. Eventually, we came upon some examples of sandstone from the Bloomsburg formation. This sandstone, from the Upper Silurian period, is red in color from the oxidation of its iron content.

Matt also told us much about the topological features of Mt Massanutten and showed us one of the springs that feeds Mountain Run. Best geology class ever!

– Art Fovargue, Cohort VII, July 2021

The photo at the top of this post shows Matt pointing out Massanutten sandstone outcropping from the Silurian period. Photo by Art.

Click on a photo below to start a slide show to see them better. Thanks to Art, Jeanine Botkin, and Sharon Landis for the photos and captions! 

“Master Naturalists are just like normal kids (ahem … people) …. as they read the words on this marker, looked around until they found the trail camera, and then hammed it up, waving and smiling.” – Sharon Landis, Cohort VII, on the Fridley Gap Field Trip, July 2, 2021