The coldest, driest phases of the most recent Ice Age created an environment of sparsely vegetated grasslands across much of North America. The sand from dried out river beds, and the rock dust from glacier-scoured boulders blew over the landscape, burying many living plants and dead animals. Much of this sand and grit was deposited in the Tunica Hills region located in northeast Louisiana, southeast Arkansas, and northwest Mississippi. (See also https://markgelbart.wordpress.com/2011/08/28/the-fossil-rich-region-of-tunica-hills-louisiana/) Streams along the Mississippi River and the great river itself erode through the loess deposits and reveal many Ice Age fossils. The Looper family prospects for fossils here, and they have an outstanding collection that they have posted online. http://www.cwreplicas.com/index1.html
Their collection includes over 500 specimens of mammoth, mastodon, Jefferson’s ground sloth, bison, woodland musk-ox, llama, stag-moose, white-tail deer, long-nosed peccary, horse, tapir, giant beaver, beaver, giant short-faced bear, black bear, dire wolf, raccoon, manatee, giant tortoise, unidentified bird, flathead catfish, and small mouth buffalo. The family also finds and collects Civil War artillery and cannon shells; Indian artifacts such as arrowheads, pottery, and atlatl weights; and Eocene Age marine fossils–sea shells, shark’s teeth, and whale bones. Lonnie Looper makes and sells replicas of fossils and artillery shells. I think I may order his replica of a stag-moose tooth which is a particularly rare fossil find in the southeast.
Before the Looper family found the 3 specimens in the below photograph, the stag-moose (Cervalces scotti) was only known from 1 other fossil site in the southeast–the Ashley River near Charleston, South Carolina, and that was just 1 tooth.
Artist’s rendition of an extinct stag-moose
The stag-moose is an extinct species of deer that was formerly more common in wetlands just south of the ice sheet in what’s now Ohio, New York, and Pennsylvania; but apparently a few wandered as far as the mid-south. Although the common name is stag-moose or elk-moose, it was not closely related to the modern moose. It was slightly larger than a modern day moose, but its head was more similar to that of an elk, and it had an antler structure unlike any extant species of deer. It was probably a solitary animal and on occasion in the vast unimpeded wilderness of the Pleistocene a few ranged down south from their more usual stomping grounds in the midwest.
The other really unusual and rare fossil from the Looper collection is the radius-ulna of a manatee in the below photograph.
If my anatomy is correct, I believe this is the front flipper. Today, manatees are not found in the Mississippi River, though they occur in brackish lagoons on the west and east coast of the Gulf of Mexico. This fossil is evidence that during warm interglacials and interstadials manatees ranged farther north than they do today because they can not survive subfreezing temperatures. One radio-collared manatee did swim as far north as Rhode Island but then returned to Florida before the onset of cold weather. Various 18th century accounts report mass manatee strandings on the coast of Britain, so they are known for going far off course. A fossil of a manatee was also found near a creek that feeds into the Ohio River, but the radio-carbon date was just 2,000 BP. Either the bone was carried by an Indian, or there was a population of manatees in the Ohio and Mississippi Rivers that recently. Dr. Daryl Domning, a scientist from Howard University, speculates the Little Ice Age that lasted from 1300-1850 may have doomed the manatees from this river drainage system.
During the Pleistocene and possibly the Holocene manatees lived in the Mississippi River.
Dr. Domning noticed that fossils of early Pleistocene manatees (Trichechus manatus) dating to about 1 million years BP are more similar to the subspecies of modern manatees (T. m latirostris) than those of the late Pleistocene manatees (T.m. bakerorum) found in Florida sites. He theorizes that colder climate caused the complete extinction of T.m. bakerorum. After the climate became warmer T. m. manatus recolonized Florida from the Carribean, explaining the close similarity between T.m. manatus and T.m. latirostris.
Scientists believe manatees colonized Africa millions of years ago by traveling in a “lens” of freshwater expelled from the Amazon River. Evidentally, they can spread across wide bodies of saltwater and survive in regions as long as temperatures stay above freezing.
“Fossil Sirenia of the West Atlantic and Caribbean Region VII. Pleistocene Trichechus mantus Linneaeus, 1758”
Journal of Vertebrate Paleontology 25 (3) September 2005
Williams, Michael; and Daryl Domning
“Pleistocene or Post-Pleistocene Manatees in the Mississippi and Ohio River Valleys”
Marine Mammal Science 20 (1) January 2004