Inaugural Dig

June 2, 2012

The Iowa City contingent arrived at the mammoth site about 8:45 AM to find some volunteers from the Ames and Des Moines areas already present. After introductions, the group walked to the dig area.Some volunteers began deepening the streamlet that cross cuts the site to better drain the bone concentration area. Others began removing spoil and overburden lying between the discovery excavation (femur) and the streamlet while another group screened spoil from the femur excavation the landowner had placed on the terrace overlying the bone bed. Screening back dirt from the discovery excavation was necessary because the landowner has recovered foot bones from the spoil. Two screens, borrowed from the Office of the State Archaeologist were assigned to each spoil pile.A backhoe with an extender for the bucket, borrowed from Titan Machinery of Oskaloosa assisted the creek side work by lifting matrix six feet from creek level up to screening areas on the terrace.

Volunteers working to deepen drainage from the area immediately discovered a vertically- oriented rib in the stream bed. The rib could have been reworked from either bank or 1-2 meters upstream where the mammoth bone concentration appears to be. The rib exhibited obvious evidence of gnawing by a large carnivore. By 10:45 a rib previously noticed in the bone bed by the landowner was encountered and, as the excavation area was expanded, another complete floating rib and two foot bones were collected. A vertebra, with epiphyses not fused, was struck by the backhoe while removing spoil at creek level. The pieces were recovered from the screens and the vertebra will be repaired in the MNH. A spruce (?) log about 2.5 feet long and 6 in. in diameter was collected from the bone-bearing deposit, also a couple of honey locust pods.Numerous other plant macrofossils appeared on the screens but none were collected because of possible contamination. Excavation ceased about 4:00 PM.

Vital information acquired is that any fractures in mammoth bones widen rapidly with desiccation and the fracture spreads. Uncovered bone will have to be shielded from the sun and kept moist unless collected and bagged immediately. Solid specimens hold up well upon exposure. It also is apparent the bone bed is normally above the water table as well as the level of the little creek that transects the site. Inundation should not be a problem during future excavations.

Holmes Semken, David Brenzel and Sarah Horgen, June 4 2012