Geologists have an interesting symbiotic relationship with highway departments. A knowledge of local geology is necessary for building a road or bridge properly. At the same time, road construction often exposes rocks that otherwise would be inaccessible for study.
Because road construction is time-sensitive, we don’t always get a lot of warning when interesting rocks are exposed. This morning we received a call from Dave Woolley, a geologist with the Virginia Department of Transportation, that they had uncovered some Triassic rocks in Pittsylvania County while excavating to install new bridge pilings on a local road. Richard Hoffman (VMNH Director of Research), Jim Beard (Director of Earth Sciences), and I rushed out to the site to see what they had found.
The Triassic rocks are the black ones exposed in the floor of the stream (VDOT temporarily diverted the stream for the excavation). Part of the fun of geology–I got to climb down into the mud to measure the orientation of the rocks (important for mapping the deposits.)
VDOT thoughtfully made a pile of the material off to the side, so that we could look over it and load it in our truck. At a glance it’s not much to look at, but the rock is very carbon-rich, essentially coal in places, and so likely to contain plant fossils. We brought a truckload back to the museum where we can clean it and examine it more closely.
Even without cleaning, a quick look at the rocks reveals tiny pieces of plant material, as indicated by the arrows:
It’s possible, but unlikely, that we may recover more visually impressive specimens from these samples. But they have already proven useful, in giving us another bit of information about the extent of the Triassic rocks in the Danville basin.
Thanks to Dave Woolley at VDOT for contacting us about this site, and making it accessible to the museum.