The Thrill of Discovery
Elevation Science field participants and staff find a new bone at the M&M site. Image by Margaretta Walton.
One of the biggest reasons people get interested in paleontology, and field science in general, is for the thrill of discovery. There’s no feeling quite like the realization that you’ve just found something new, a piece of prehistory never seen before by another human being. I was lucky enough to get a chance to experience that feeling this summer after two of our participants discovered the well-preserved skeletal remains of a large dinosaur near our Andersen Area sites.
It was early August, we were preparing to wrap up our digs for the summer. This week was also Academy Week, when our wonderful friends from the Academy of Natural Sciences in Philadelphia came out to the field with us. That day, the whole crew was exhausted and the temperature was climbing up through the 90’s. Daniel and I had just wrapped up work on our fossil tree quarry the day before, where we had spent most of our field days at Andersen Area this summer, so I went to help out at a different site. It was a slow, quiet morning at Fossil Flats, a site likely containing the bones of a Camarasaurus, with Skye managing the quarry and a few of our Academy members working with us. I was sitting in the dirt, picking away at the matrix on a neck vertebra in the blazing summer heat and reacquainting myself with the site I had barely seen this summer.
Around noon, two of our Academy participants, Meg and Margaretta, returned from a prospecting trip to check in at Fossil Flats. They were holding large chunks of rock, which they presented to Skye and myself, asking us to confirm if they had found pieces of petrified wood. Skye and I immediately knew that these fossils were no petrified wood. Meg and Margaretta had found a dinosaur! With Skye staying at Fossil Flats to oversee the quarry operations there, I joined our participants to return to the site where they had discovered these bones, eager to see if anything else was left there.
On our trek to return to the site of their discovery, we stumbled upon another interesting find. Tracing along the edge of a gully, we walked over a flat area covered in sparkling, bright white stones. Upon closer inspection, this turned out to be petrified wood, and lots of it. Lying across the ground were dozens of pieces of fossil wood, bleached white by the sun with lichen growing on them, indicating that they had been exposed to the elements for a while now. Some of these pieces of wood had little knots and burls, and others were composed of crystals that glittered in the sun. We collected a couple hand samples and marked the site on GPS, but we didn’t have much time to waste standing around and appreciating this fossil tree. We had to find the dinosaur, and determine if there was any more to the bone chunks that Meg and Margaretta brought back to Fossil Flats.
Margaretta was the first to spot the bones again, sitting next to a couple of sage bushes a short walk from our LZ Blue site, and Meg and I ran over to join her. In the spot where they had picked up the chunks of bone was a pile of broken fossils, some pieces up to the size of a fist. Some of these pieces contained gorgeous crystals that filled in the hollow core of the broken bone. But these dinosaur bone geodes, formed by the mineral calcite precipitating into the hollow core of the bone and slowly growing crystals, are more than just pretty rocks. Based on the hollow structure of the bone, it was clear that what we were looking at was a long bone, like a femur or tibia, of a theropod dinosaur.
Theropods, the group of dinosaurs that includes fearsome carnivores like T. rex and Velociraptor as well as modern birds, were the top predators of the Morrison Formation. While other dinosaurs did have lightweight skeletons, theropods have distinctively hollow bones, which would be useful later in theropod evolution since they gave flying birds lighter skeletons. This trait is also useful to paleontologists, as it allows us to make a quick identification in the field. Although we could not be sure of the specific theropod genus or species based on what we saw here, this one is definitely big! The most common large Morrison Formation theropod by far is Allosaurus, the so-called “lion of the Jurassic”. The Elevation Science team has already excavated a couple skeletons of Allosaurus from this area, so there’s a possibility that we have another of these formidable Jurassic predators on our hands!
Our next step was to figure out how much of the skeleton was left at this site. While the calcite-infilled long bone pieces were beautiful, they are not of much use to science without the rest of the skeleton. We also needed to figure out if there were any bones left in situ in their original positions, or if this long bone simply eroded out of another location and was transported here alone. This spot was on relatively high ground, in an area with a decent amount of plant cover, both of which are good indicators that this bone probably eroded out of the ground right where we stood and the rest of the skeleton could be buried below us. On high ground, the bone is unlikely to have been washed downhill from another location, and the plant roots both help keep the soil stable and leach minerals out of fossils under the surface. While these are good indicators, the only sure method to finding more bones is to start digging, so we pulled out our brushes and got to work.
It didn’t take long before we started finding bones under the surface! After brushing away a couple inches of dirt, we discovered more intact fossil bones in fantastic condition. One of these bones was the flat end of a cylindrical bone, the centrum of a vertebra. The more we looked, the more bones we found, and the more our excitement grew. We informed the rest of the crew that we had fossils in situ here, and it might be worth it to mount a full excavation at this site! Before long, the site had been given a nickname: “M&M”, in honor of its discoverers Meg and Margaretta. But unfortunately, we had less than two weeks left in the field this summer, and the crew were now left with the difficult task of closing up the site as soon as we found it.
Meg, Margaretta, and Katie in the lab. Image by Meg Lemieur.
With only a couple of hours to safely preserve and collect all the fossils we could, we got to work. A couple other crew members came to join us and drop off supplies, and we quickly set up a system of stabilizing, labeling, and wrapping up the smaller pieces of bone. I was busy cleaning off one of the unidentified bones we found under the surface and making winter jackets, while the rest of the team managed to pack up dozens of bone fragments for transportation back to the lab before we covered up and buried the site to wait for our return next year.
The bones from the M&M theropod are now back in the lab, with Meg, Margaretta, and our lab manager Katie getting all the fossils cleaned up for study. As we get more material prepared, we will connect more pieces of this prehistoric puzzle, learning about what this dinosaur was and how it lived. And of course we will be back next field season to see what other treasure is in store at the M&M site, so stay tuned for updates on this exciting find!