Birds and Nature North America

Blog #4. Glendive, Montana. 17 May 2020

The Hell Creek Formation, Dinos, and the K-T Boundary

Adult male Lazuli Bunting, common the the dry lands of Glendive, MT

I had made an arrangement with Shana Baisch to visit her ranch to have a look at her rich fossil-bearing badlands just east of the town of Glendive. Most (all?) of her ranch lies in the Hell Creek Formation—mainly terrestrial and subtropical upper Cretaceous and lower Paleogene sediments famous for their dinosaur fossils: T. rex, Triceratops, Edmontosaurus, and more. On my 2019 field trip I had tried to visit Shana’s dig site but got rained out. This year the weather was favorable and she took off a Sunday morning to show me one of her nearby badland sites.

Shana Baisch on pasture leading to badlands (in background)

For several generations, the Baisch’s have run several hundred head of cattle on some 13,000 acres of upland prairie and badlands. Shana’s mother-in-law Marge, got the fossil bug decades ago, and her interest and dedication led the family into some serious fossil exploration and excavation. This is permissible because the sites where they collect are privately-owned land.

female Bullock's Oriole

Shana has taken the lead on the fossil work for the last five or so years. Each summer and fall the family hosts a stream of visitors to their badland collecting field trips. I was experiencing that special experience (to learn more or plan a visit, visit her website at: http://www.dailydinosaurdigs.com/). Sadly, the 2020 summer season has had to be cancelled because of the COVID-19 threat.

We could drive right up to the fossil-rich badlands

After I arrived at her ranch from my campsite at Green Valley Campground, just off I-94, Shana and I drove up through a winding prairie trace of a ranch track to a low mound that featured a long-term dig they were carrying out.

Triceratops excavation site

Here was the skeleton of a Triceratops just below the surface of this low hilltop. Baisch and her team were patiently extracting the skeleton from the Hell Creek sediments. It is painstaking work, to say the least. They have been working on this dig for more than a year.

Mandible of the Triceratops

Here (above) one sees a mandible of the Triceratops still needing to be fully extracted from the sediments. This is a multi-season effort, involving various players—both volunteers and experts.

rib bone of the Triceratops

Here (above) is another bone of the Triceratops. Several years ago Shana and her team needed heavy equipment to extract the giant skull of a Triceratops from another site on the ranch. That skull is still under meticulous preparation in a ranch work building.

Shana, near where she recently found the T. rex tooth

After examining the Triceratops skeleton excavation site, we drove up into the badlands and had a look around. We searched for fossils eroding from the cliffs or hilltops. It is not uncommon to come upon fossil dinosaur bone or turtle shell right on the surface, ready to pick up and admire.

Fossil dino bone right on the surface of the bare ground

Shana pointed out various dinosaur and other vertebrate fossils that were weathering out of the matrix. It was amazing to see these 66-million-year-old remnants of past life. Also we encountered agatized wood and petrified wood.

agatized wood

We hiked up to a dark band in the sediments that apparently is the K-T Boundary (the sediment layer memorializing the great asteroid strike that ended the Cretaceous and ushered in the Paleogene (=Tertiary) Era. It was remarkable to be digging into the narrow carbon-black layer exhibiting what looked like sparkly coal-black fragments, perhaps caused by the great fireball. The April 2019 New Yorker story entitled “The Day the Dinosaurs Died” provides a bone-chilling account of what exactly transpired when the asteroid struck. It’s worth a read!

dark layer is apparently the K-T boundary, marking the moment when the asteroid struck

close-up of the K-T boundary - everything burned up and carbonized

Just two weeks before my visit, Shana had found a large tooth of a T. rex in the very cliff where we were clambering about. The tooth had just worked its way out of a cliff (this reminded me of finding large Megalodon shark teeth that erode out of the sediments of Calvert Cliffs in Maryland. Holding that T. rex tooth is something else! What a find!