Public fossil dig at Pembina Gorge had over 630 volunteers

Bucket lists are popular these days, and Walhalla is a destination that is on more than a few of those lists. The dig site at the Pembina Gorge in Walhalla is a magnet for armchair archaeologists and wanna-be geologists searching for that lost goldmine of hidden fossilized gems laying under the next layer of dirt.

Posted 08/31/2018

By Lisa Nowatzki

For the 2018 Public Fossil Dig, co-sponsored by the North Dakota Geological Survey (NDGS) and the North Dakota Parks and Recreation Department (NDPRD), more than 630 volunteers armed with brushes and trowels turned out to help at 40 archaeological sites across the state.

The Walhalla site dates for 2018 ran from August 7 thru August 11. For a full day of digging, adults paid $89. The fee included breakfast, lunch, snack, transportation to the fossil site from Frost Fire Ski Resort, and a souvenir. The Pembina Gorge site had 136 people attend the public fossil dig at Walhalla. They also had two paleontologists, a field intern, and a couple of experienced diggers helping out as well.

Scientists working on the Pembina Gorge dig site claimed to be searching for sea monsters, mosasaurs to be exact. In previous years the groups found two partial mosasaur skeletons, and last summer, they started on a third. One recent Facebook update on the NDGS Paleontology site declares that they have rediscovered the bone layer again from their new species of mosasaur! Looks like they might be getting into the body region with a few more ribs.

According to Clint Boyd, Senior Scientist at NDGS,  the 2018 Pembina Gorge dig was very productive. “We did find several more bones from the mosasaur we have been working on since 2015, mostly ribs and vertebrae. We also found a new mosasaur specimen in another spot and got several skull bones including parts of the jaws with teeth still in them. Our hope is that these bones will eventually go on display somewhere up in the Pembina Gorge area once they are fully cleaned and ready for display.”

Other fossil specimens were also collected. “We collected quite a few bones from the spine of the large fish Xiphactinus exposed on the surface on the first day of the digs. It took us until the last day of the dig to work our way up the hill and find the level where they came from. We ended up with a few dozen vertebrae from the backbone but hope to find more as we dig in next year.”

The area around the Pembina Gorge dig site is called the Pierre Formation and is around 80 million years old. During that period the area was covered by water and was home to large swimming reptiles called mosasaurs, giant squid, sea turtles, aquatic birds, large (and small) fish, snails, clams, and more.

According to John W. Hoganson, several hundred fossils have been recovered at the Pembina Gorge site. Most of these fossils are disarticulated, isolated skeletal parts of several vertebrate animals. They are encrusted and impregnated with gypsum and are poorly preserved. Vertebrates found include mosasaurs, fish (Enchodus, Xiphactinus, Stratodus), plesiosaurs, and birds (Hesperornis regalis).

Though the site has yielded some wonderful mosasaur fossils, evidence of other sea monsters was also discovered. One invertebrate fossil, Tusoteuthis longa, was discovered at this site. Tusoteuthis longa is the scientific name of the giant squid which is believed to have been similar to the living giant squid Architeuthis dux. The squid fossil found at the Pembina Gorge site in 2002 is roughly six feet long!

The public plays an important role in the hunt for fossils in the Gorge area. Boyd details some of the discoveries by the public in the January issue of Geo News. In July of 2015, 17-year-old Deborah Shepherd from Green Cove Springs, Florida was visiting the Pembina Gorge State Recreation Area with her family. While visiting the site, Shepherd found a fist-sized piece of white bone encased in a crust of black shale and, alongside the bone, four large teeth. Deborah had found part of the jaw of an ancient sea monster: a mosasaur.

Boyd also writes about another valuable find by the public. In the spring of 2016, a student from the University of North Dakota was biking the trails in the Pembina Gorge when he noticed some bones poking out of a hillside and reported the find.

With his assistance, NDPRD and NDGS staff visited the site in the summer of 2016. Those fossils were from another mosasaur preserved in the Niobrara Formation, which is situated below the Pierre Formation. Very few fossils have been found from the Niobrara Formation in North Dakota, so this find is an important discovery.

Some volunteers and members of the public want souvenirs from the dig to take home. This is not possible because North Dakota Century Code forbids removal or destruction of any paleontological find on state, federal, or otherwise public land. “Any paleontological resource found or located upon any land owned by the state or its political subdivisions may not be destroyed, defaced, altered, removed, or otherwise disposed of in any manner without approval of the state geologist.”

According to the NDGS Paleontological resources page, land owned by the State of North Dakota and its political subdivisions, are protected and managed by the North Dakota Century and Administrative Codes, respectively. A permit is required to investigate, excavate, collect, or otherwise record paleontological resources on these lands.

The rules also provide a mechanism for monitoring paleontological activities on State lands, thereby providing information for State resources management plans. For rules governing the collection of fossils on federally managed lands, please contact the appropriate governing entity like the Army Corps of Engineers or the United States Forestry Service.

If a member of the public is caught with an unauthorized fossil, the penalties are steep. “Any person violating any paleontological provisions of the Century Code is guilty of a class B misdemeanor and shall forfeit to the state all paleontological specimens discovered by the violator at that site. Any such violation is considered to have been committed in the county where the exploration, collecting, or excavation for paleontological resources was undertaken.”

The value of these finds cannot be undervalued. All of the fossils found in ND represent a part of ND history that lends to the understanding of the development of the local area and land that cannot be replicated or duplicated.

Boyd explains, “We are trying to learn more about what the environment and animals were like in the area of the Pembina Gorge 80 million years ago. Every new fossil we find adds to that story. Most of the information we gather requires very minimal technology, though 3D scanners and printers are very useful for designing exhibits and sharing information with the public and researchers across the planet.”

Scientists like Boyd have learned much about mosasaurs and their place in prehistoric biospheres. “Mosasaurs were large aquatic reptiles that lived in the oceans during the Mesozoic Period while dinosaurs were ruling the land. Though they lived at the same time as the dinosaurs, they are actually more closely related to snakes and monitor lizards (like the Komodo dragon) than they are to dinosaurs.

They swam using four large flippers and an extremely long, stiff tail, and had to return to the surface to breathe, just like modern whales and dolphins. They were the top predators of the seas during their time, with some species reaching lengths of close to 50 feet and displaying teeth as large as that of a Tyrannosaurus rex.”

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