Excavations continued the weekend of October 4-5, 2003. Eight volunteers departed for the sloth site Friday afternoon, October 3, in a university van to empty the whirlpools immediately downstream from the bone deposit and search for any bones that may have been transported and dropped there because of reduced velocity.
As noted previously, the channel of the Tarkio bisected the area between the rib cage and the scapula with an indeterminable amount of bone possibly removed. A series of four deep whirlpools had formed approximately 20 meters downstream from the site, probably the result of the 1993 flood, but possibly later. Any bone that was removed before the pools formed likely was transported far downstream and is probably lost, but we believed that any bone moved subsequently as bed load would be trapped in the pools.
The ditch constructed on the previous trip diverted the stream but the low gradient permitted some backwater to enter the pools. While we were traveling to Shenandoah, landowner Bob Athen sandbagged to prevent backflow and used rented a gasolinepowered pump to start emptying the pools. By the time the crew arrived at 8:00 AM Saturday the water level had dropped significantly, especially in the shallowest pool, furthest upstream. Unfortunately as the water level dropped, especially in the deeper pools, the ability of the pump to lift the water out declined drastically, forcing the crew to organize bucket brigades to completely empty the holes.
The crew brought a screen (approximately 3’ X 6’) constructed from 2X4’s and 1/4 inch hardware cloth and mounted it on two saw horses immediately downstream from pool nearest the sloth (upstream end). A team of bone-pickers arrayed themselves around the screen and began sorting through material dredged by the bucketful from the bottom of the pool. A significant amount of sand and black muck accompanied each bucket and necessitated rinsing with several buckets of water. All bone fragments, in fact anything that caught the eye of a crew-member, was saved for evaluation in Iowa City.
Pumping continued all day and as the water level dropped, each pool was emptied, and the screen was moved to the next pool downstream. A youthful local by-stander was recruited to rescue catfish from the pools.
Searching renewed Sunday at 8:30 AM and continued until noon. The water level in the enclosed area had dropped sufficiently for the pump to be redeployed to rinse the dredged material. Time prevented the complete evacuation of all of the pools, but they largely were cleared without revealing an obvious sloth bone. Subsequent examination of the bone retrieved only produced remains of modern farm animals: horse, cow, deer, etc.
A couple of the deeper gravel stringers leading downstream from the sloth deposit were screened for bone and one of these produced a large fragment of a sloth bone (unidentified) approximately half way between the site and the uppermost pool. We concluded that if any bone removed from the channel occurred before the whirlpools formed and will not be recovered.
Participants; David Brenzel, Shara Rowley, Sharon Benzoni, Eu-Jin Kim, Dana Clark, Molly Martens, Emily Glonek, Lynette Stephenson.
David Brenzel, October 11, 2003