Summer 2019 - By Dr. Jim Mead, Mammoth Site Director of Research

 

How was this summer’s Ice Age Explorers dig?         

“We had a great group of folks throughout June for our Ice Age Explorers season. Two newcomers and the rest as return folks.  All was fantastic. Some folks excavated the entire time, some sorted bone from Persistence Cave, some worked on preparation, and some mixed-n-matched as they wanted.  It was wonderful.  So much was accomplished.  In the east end of the sinkhole, I had the excavators basically chop out chunks of clay and then split them along the bedding plane which was usually a thin layer of silt or sand. In so doing we are now fairly consistently recovering plant remains – bits and pieces of wood and grass being replaced by iron and or manganese.  Marianne did recover what appears to be a very nice insect leg.  A single fish remain upon detail examination is actually two fish skeletons.  So our approach is paying off nicely.  Fairly large areas were taken down. Previously discovered remains (such as an articulated foot) were fully exposed.  We are nicely getting toward following the ‘bone plane’ that includes Murray heading deeper and toward the center of the sinkhole.  Although there is obviously much more to do, the course is set for a couple of years to come.  A couple of folks worked diligently on defining the sinkhole edge and contact with sediments and bones – this is a critical location towards the southeast end that we need to better understand to define the wall of the sinkhole.  Biz ‘and gang’ removed the large mandible at the southwest end where Vee’s skull was removed years ago – this area is now unofficially labeled “Bizneyland.”

 

What is the latest on the Snake River Fossil Site?

“In earliest May, Sandy Swift, Sharon Holte, Presston Gabel, Biz Storms, Bethany Cook, and a number of colleagues from Texas, Arizona, and Wisconsin, and joined by two experienced Ice Age Explorers (Lynn and Susan), helped me analyze the bison coming out of a bog deposit in Tom and Gail’s Snake River Farm (south of St. Cloud, eastern Minnesota).  We did this early in May to avoid the mosquitos of later May and June but that meant we might have rain and snow…which we experienced in all its glory!! Fun in the mud is the bottom line.  We have now pretty much cleaned all the recovered bison bones and begun analyzing all for details. I hope to have a radiocarbon date on a beaver-chewed stick by the end of summer. This should provide an age for the beautiful adult female Bison antiquus skeleton Arturo Baez was recovering.”

 

What have you been up to this summer?

“It has been a very busy summer for me (see above).  Sandy and I attended the Biology of Pitvipers conference in Rodeo, New Mexico, where we presented our work on the morphology of the skull of Asian and North American vipers.  Then we went on to work with colleagues Dr. Steve Emslie (MS Science Associate, U NC Wilmington) and Larry Coats (University of Utah) on two caves in the Northern Snake Range of the Great Basin at the Nevada/Utah border.  I worked this area back in the late 1970s and early 80s. In August I headed to Hills, Minnesota to understand the mammoth and bison remains being unearthed in a farmer’s backyard.”

 

What can we look forward to in new publications?

“Publications are coming together regarding proboscideans from all National Parks in the USA and an overview of the Ice Age fossils, environments, and cave localities in Grand Canyon National Park, Arizona.  Plans are being made for late September to work with NPS folks about another cave excavation along with helping the 100-year-old Grand Canyon National Park celebrate National Fossil Day. From there Sandy and I head to two caves in the Trans-Pecos region of west Texas, to help archaeologists understand the mats of Shasta Ground Sloth dung being discovered below cultural layers.  And of course Sandy, Sharon Holte, and I with the help of Dr. Chris Jass (Royal Alberta Museum) will continue our work in September on excavations and faunal remains from Persistence Cave and Parker’s Pit here in the Black Hills.”

 

How did the Intern program go this summer?

“Once again we had 10 interns for our summer season.  A great and diverse set of college and graduate students from around the country were divided into education and paleo-conservation groups. All were of a great help.  And all were still housed in our current (and inadequate) dorm housing.  We hope that The Mammoth Site Field Station that Presston and I have been planning for some time now will actually be on-site come September.  This field station will permit us to have definitely better housing for our interns but also for a number of visiting researchers and summer field school projects from visiting colleges around the country wanting to study in the Black Hills region.”

Snake River Fossil Site May 2019 Expedition

1.    What do bison have to do with The Mammoth Site?

The Mammoth Site albeit focuses on mammoths, yet the research conducted here really is about ‘everything Ice Age’.  Our research will concentrate on predominantly the Black Hills and that undefined fringed around it (WY, SD plains, NE), we do have other Ice Age projects in caves within the Grand Canyon and in the central Great Basin (Nevada).  So – our study of the Bison and then how we teach about their evolution and exhibit them in our museum area is right in line with our mission.  Interestingly, there are no bison fossils in The Mammoth Site sinkhole deposit.  The reason seems to be that the sinkhole sediments which are dating about 140,000 back to greater than 190,000 years old are before bison were here, or at least common, in North America south of the Canadian ice caps during the glacial period.  As ice began to melt, causeways opened up from Beringia (that region from the Yukon, Alaska, to Siberia) allowing bison to disperse south into what we know as the USA and into Mexico.

2.    All in all, how did it go?

Our excavation from May 4-10 was terrific.  We were able to locate what appears to be a large bone bed of bison skeletons which the Snake River let us see it by carving a path through the center.  We are not sure just how great an expanse it covers but we know it has some very large bison in it (some researchers would say that these are Bison antiquus, the extinct Ice Age bison) and some are smaller, about the size of our existing bison (Bison bison). The bison of today are actually the smallest bison that have ever existed.  The bison bone bed  is about 12 in. (20 cm.) below current river level so excavators are always deep in black bog mud!  We know that we will go back to the Snake River Farm in 2020 to open up a larger area of the bone bed to better understand it. Questions that I have include: how many bison are there?; how many years ago did this bone bed happen?; why was the bone bed created – what caused it?; what time of year/season did it happen?

3.    What did you find and what would you say is the most remarkable find?

We found LOTS of bison bones. Some were disarticulated and some were articulated (in life position and connected). We have many individual ages of bison – i.e., it was a herd of some sort and some size.  The most remarkable find I think is that we have so many LARGE bison.  One skull is of a probably 12-14 year old….big and heavy. At first I thought it was a bull but the horn cores indicate it is a female.  I feel pretty confident we have at least some Bison antiquus.  We also found some turtle and MANY lengths of wood with many chewed on by a beaver!

4.    What happens next to all these bones?

So  the skeletal remains that we removed will now be cleaned up – to get all the bog mud removed.  They will be dried out and repaired if they need it. Then we begin the long process of determining what skeletal elements we recovered, do some measurements, and then surely get a radiocarbon date both on the beaver-chewed wood and the bison bone.

5.    When is the next dig and what do you hope to find?

Our next excavation is tentatively planned for early May 2020.  We want to avoid the mosquitoes but the price to pay for this is be ready for lots of rain and some snow (as we had this year!).  I want  to find out how big a bone bed we have and answer the questions that I presented above.  In any case, it will be extremely interesting and fun!!

Bison Skull & Vertebrae
Bison Skull & Vertebrae

Bison Skull & Vertebrae at the Snake River Fossil Site.