OSKALOOSA — University of Iowa scientist Art Bettis traveled to the mammoth dig site in rural Mahaska County Saturday to study sediment layers to learn about the area's ancient past.
There has been more excavating at the dig site to widen the search area. This digging shows sediment layers that give insight into the conditions in the area where mammoth bones have been found. Bettis is an expert in studying sediment.
"We know the mammoths are last glacial," Bettis said.
However, there are some darker sediment deposits in the area that indicate that soil is younger than its surroundings.
"We have some nice exposures here," he said.
Bettis said he would like to bring a boring rig out again to do more soil sampling.
There is a terrace area on the westside of the dig site that is late glacial. The northside of the dig site is older than the westside. The northside is late interglacial, under 125,000 years, he said.
Dave Brenzel of the Indian Creek Nature Center in Cedar Rapids also was at the dig site, and he had some more mammoth fossils to show off.
Brenzel and the property owner brought out a Spinous Process of the vertebrae.
"It's the bump on your backbone," he said.
The Spinous Process was 21 inches long.
"That's a huge bump," he said. "The length and the thickness impresses us."
Brenzel held the Spinous Process that was found a the site two weeks ago next to a Spinous Process found a year ago. They were of a similar size.
A group from Grinnell College arrived Saturday morning to work at the site, Brenzel wrote in an email.
The group had nine students from the introductory geology class taught by Assistant Professor Dr. Andrew Graham. He was accompanied by biology professor Dr. David Campbell and Dr. Ken Christianson, biology professor emeritus, plus spouses. Everyone got especially muddy after the overnight storms but they all pitched in hauling out the muck that had washed into the pit and they all found bones, mostly skull fragments — nothing large though, Brenzel wrote in the email.
Herald Editor Duane Nollen can be reached by email at email@example.com