Aquatic Ecology & Palaeoecology Research Program
The remains of the Scrivens Mastodon were first discovered by Veronica Scrivens on property owned by her and her husband Aaron. One year after the digging of a pond in front of their home, Veronica noticed a bone sticking out of one of the piles of dredged pond sediment. Being a hunter and one who is no stranger to animal bones, she immediately knew that it was too large to be a deer, cow, or horse. She brought the bone to Hillsdale College Professor, Dr. Anthony Swinehart, for identification. The bone turned out to be the left ulna (forelimb bone) of an immature male mastodon. The Scrivens invited Dr. Swinehart to coordinate a search for the rest of the skeleton and a subsequent scientific study of the site.
An irrigation pump was employed to drain the pond so that the bones and other fossils could be reached.
An erosion control structure was built to prevent damage to nearby wetlands.
Draining Scrivens Pond
With the assistance of Justin Pung of the Michigan Department of Environmental Quality, Hillsdale College received a permit to drain the pond and remove sediments in order to locate and recover the skeleton. An irrigation pump was used to drain water, and an erosion control structure was built to avoid damaging nearby wetlands.
Scrivens Pond as it drains...
Draining Scrivens Pond was only the beginning of a long messy process to find and access the bones of the mastodon.
Finding the Mastodon
Draining the pond was only the beginning of a long, messy, and difficult process of finding the mastodon. Because the first bone discovered came from spoil dredged from the pond over a year before, the exact location of the rest of the skeleton was not known. Although the pond is less than an acre in area, finding the source of the bones was like searching for a needle in a haystack. The drained pond left behind aquatic plants, and a mucky ooze over a meter deep that made walking on the material impossible. Volunteers had to crawl with the aid of boards to access the pond bottom.
During the winter, a ground penetrating radar unit was systematically moved over the ice of the pond to try to locate the bones. This proved unsuccessful.
High-Tech and Low-Tech Remote Sensing
During the winter months, Ground Penetrating Radar was used over the ice of Scrivens Pond in an attempt to locate the bones remotely. This proved unsuccessful. Therefore, after the pond was drained, metal rods were used to systematically probe the pond sediments at 1 ft intervals. This required numerous volunteers and many, many hours of work. Probing also proved unsuccessful, which led the research team to conclude that the mastodon was underneath fill that was placed at one end of the pond many decades ago. A hydro-hoe was used to peel back fill that covered part of the ancient wetland.
The Site of the Mastodon Carcass is Located
After two weeks of hard work, progress is made. Within a meter of the edge of Scrivens Pond, underneath old fill, a rib of the mastodon was discovered in place! The research team could now focus its attention on a careful scientific study and excavation of the carcass. Many of the bones had been removed by heavy equipment during the digging of the pond two years previous, and an entire skeleton was not present. However, many large bones representing different skeletal elements were recovered, including both humeri, the left ulna, many anterior ribs, a posterior rib, part of the scapula, and a thoracic vertebra and vertebral epiphyses. From a scientific perspective, it is not problematic that an entire skeleton was not found. Among the most important aspects of this site are the associated plant and animal fossils that tell us what the environment was like before, during, and after the mastodon's death. Among other things, Dr. Swinehart and his students plan to examine the growth rings in the fossil trees to determine climatic conditions and patterns in the area over 10,000 years ago. This kind of research may help uncover the mystery of the extinction of the mastodons and the extinction of numerous other ice-age animals from North America.
Volunteers Explore the Spoil Pile
The excavation was a community effort, with help from Sarah and Seth Zeiler of Zeiler Farms, John Weddell of the Minihaha Foundation, Jim and Shannon Vandusen, Mike Rose, and Brian Auby from the Hillsdale Rural Fire Department, and members of the greater Hillsdale community. Numerous students and faculty from Hillsdale College, as well as students from Jackson Community College and the University of Michigan Dearborn also helped with the excavation. Chase Beck, a biology student at Hillsdale College, is studying the site as part of his bachelor's thesis. During the excavation, students from several local schools participated in field trips to the site, where they were given a short lecture on ice-age animals and plants by Dr. Swinehart before having an opportunity to look for fossils in the dredged pond sediments. Participating schools included Davis Middle School (8th grade science), Jackson Community College (Geology class), Hillsdale Step-by-Step preschool, Hillsdale and Coldwater home school groups, Will Carleton Academy (5th Grade), Jonesville High School (biology class), and Hillsdale Academy.
The American Mastodon (Mammut americanum)
Mastodons are related to woolly mammoths and modern elephants and became extinct approximately 9,000 years ago. Current theories about the cause of the extinctions range from loss of habitat due to climate change, to human over-hunting, to bombardment by stardust from a super-nova.