EOCENE AND OLIGOCENE MAMMALS FROM THE GRAVELLY RANGE OF SOUTHWEST MONTANA

Our first paper on work that several of us are doing in the Gravelly Range, southwestern Montana, was just published in a special issue of Paludicola, Scientific Contributions of the Rochester Institute of Vertebrate Paleontology. This issue contains papers in honor of James Gilbert Honey, a paleontologist and stratigrapher who focused on the Cenozoic, particularly the paleontology/evolution of camels and the Paleocene’s Fort Union Formation geology and paleontology. We’re pleased to have our work included in this volume! You can find our entire paper at:

Rochester Institute of Vertebrate Paleontology – Paludicola:

Donald Lofgren, Debra Hanneman, Jackson Bibbens, Liam Gerken, Frank Hu, Anthony Runkel, Isabella Kong, Andrew Tarakji, Aspen Helgeson, Isabel Gerard, Ruoqi Li, Sihan Li, Zhihan Ji. 2020. Eocene and Oligocene mammals from the Gravelly Range of southwestern Montana. Paludicola 12: 263-297.

Our paper’s abstract is: High elevation outcrops of Tertiary strata in the Gravelly Range of southwest Montana yield late Uintan to Whitneyan vertebrates that comprise five mammalian assemblages; Rapamys Site, Black Butte Low, Teepee Mountain, Black Butte High, and Lion Mountain High. The Rapamys Site and Black Butte Low are late Uintan or early Duchesnean. Two new species are present at the Rapamys Site (the carnivore Lycophocyon tabrumi and the rodent Pareumys muffleri). Small mammalian assemblages from Teepee Mountain and Black Butte High are late Duchesnean-early Chadronian and Chadronian, respectively. The most diverse assemblage is from Lion Mountain High, which is correlative with Whitneyan faunas from Wyoming, Nebraska, and South Dakota. The Whitneyan age of the Lion Mountain High assemblage is further age constrained by an underlying tuff with a weighted mean 40Ar/39Ar age of 31.7 +- 0.02 Ma and an overlying basalt flow with a K/Ar age of 30.8 +- 0.7 Ma. Paleogeographic range extensions into Montana for Lion Mountain High taxa include Diceratherium tridactylum and Oxetocyon cuspidatus. The taxonomic composition of the combined Rapamys Site/Black Butte Low mammalian assemblage is most similar to those from southern California, rather than geographically closer assemblages found in Wyoming and Utah. Comparison of undescribed middle Eocene mammalian assemblages from southwest Montana to those from southern California will further elucidate the middle Eocene Montana-California paleobiogeographic affinity.

Our geology paper on this area is soon to follow….

Prospecting For Vertebrate Fossils On Hot Summer Days In Southwestern Montana

The end of July always brings The Webb School students who are interested in paleontology to southwestern Montana. That time is packed with prospecting a variety of Tertiary sites in the hopes of finding interesting vertebrate fossils. This year had its good finds along with persevering through some really hot days. Being on a surface of light-colored rocks under the intense sun while slowly looking for fossils such as rodent jaws, rabbit teeth, or even isolated horse teeth is a tough way to spend a summer day. Even prospecting for larger pieces of fossil vertebrates is no easy day, but the students hung in there. Here’s a few scenes from the prospecting adventures:

The late Eocene strata at Pipestone held the students attention for many hours

The late Eocene strata in the Pipestone area west of Whitehall held the students attention for many hours.

 

Late Tertiary outcrops north of Whitehall, Montana, yielded some interesting horse and camel remains.

Late Tertiary outcrops north of Whitehall, Montana, yielded some interesting horse and camel fossils.

 

A horse jaw and at least part of the skull was found in late Tertiary strata.

A horse jaw and at least part of the skull were found in late Tertiary strata located near Whitehall.

 

Still searching for that elusive fossil....

Still searching for that elusive fossil in the North Boulder Valley….

 

Late Tertiary canid dog skull fossil find from last season's Webb School  paleo students' efforts. Skull is now at the Museum of the Rockies.

Late Tertiary canid dog skull fossil find from last season’s Webb School paleo students’ efforts. The skull is now at the Museum of the Rockies in Bozeman, Montana.

 

 

 

 

 

 

 

For those truly interested in vertebrate paleontology, keep in mind that the renowned Raymond Alf Museum is also on the Webb Schools campus. The museum is definetly worth a visit.