When Callan Bentley was visiting us a few days ago, he found a circular depression with an elevated rim in one of the sandstone beds near Two Sisters, and wondered if it might be a sauropod track. Tracks have been reported from the Morrison on occasion, but as they’re not terribly common I considered it unlikely. Nevertheless we decided to check it out before leaving.
Here’s a wider view of the area where Callan saw his depression (the scale is 150 cm):
Each red circle marks a depression with a raised rim (they’re partially filled with mud). The vegetated area in the extreme lower left may be another one; the plants preferentially grow in the mud, since they can’t attach to the bare sandstone as well.
Now, trackways are notoriously difficult to recognize; it’s very easy to talk yourself into a seeing a pattern that’s not really there. Even so, this is pretty suggestive. Both Brooke and I were seeing the same depressions, and the elevated rims are very distinctive. Here’s one from a much lower angle:
Brooke also tells me that when tracks have been reported from this part of the Morrison, they’ve been found in indurated, rippled sandstones like this one. It’s going to require more work to confirm it, but right now these look like pretty good candidates for sauropod tracks.
Our actual goal today was to close down the site. Since that only takes a few hours, we took our time and went to Dirty Annie’s for breakfast. Big mistake! (Taking our time, not the breakfast!) While we were in Dirty Annie’s, Shell Creek overflowed its banks:
This is a problem because we have to cross Shell Creek to get to the site. Here is the first bridge over the creek, closed while they try to remove debris piled up against the bridge supports to keep the bridge from failing:
We finally found an open road across the creek and, after checking out the possible tracks, started closing down the pit so we could get out before the water rose further. A look over the hill made us redouble our efforts:
This was the nastiest-looking storm I’ve seen in awhile, and it wasn’t something we wanted to be caught in, since our road is impassable when muddy. We closed the pit and made a mad dash for the paved road:
We got back to Dirty Annie’s just as the hail hit:
Not the kind of thing we want landing on our bones, or our workers:
Even with all the excitement, we managed to get the site safely closed, bringing a very successful excavation to an end. Thanks to this year’s field crew (below, conterclockwise): Tim, Nick, Nathan, Brooke, Matt, and Mike, as well as Milton, Linda, and Nancy (who had already left), with a special shout-out to Callan for the possible trackway discovery.