What it was, once the Dallas Paleontological Society investigated. The bone was a pelvis of a Columbian mammoth, one of the two largest species of mammoth.
"This area is a fossil gold mine," society member Ed Swiatovy of Sherman told the Herald Democrat of Sherman and Denison for a story in Sunday editions. "At one time, it was under an inland sea. When it came to the end of the dinosaurs, when mammals took over, this area was grass plains and woodlands -- everything that mammals like. This area has always been conducive to marine or mammal life forms."
Society volunteers have excavated the area found by the boys, dinging a shoulder bone, fragments of two leg bones, a lower jaw with teeth and the back of a skull, Swiatovy said. All of the bones have been sent to the Museum of Nature & Science in Dallas for study and carbon dating.
A team of archaeologists from Southern Methodist University in Dallas surveyed the site for any signs of prehistoric human life but found none, he said.
The area along the Red River is rich in fossils, Swiatovy said. About five years ago, a team of society volunteers recovered the remains of a plesiosaur determined to have been about 90 million years old.
The Columbian mammoth and its cousin, the woolly mammoth, died out in the area between 10,000 and 13,000 years ago, Swiatovy said. The Columbian mammoth was one of the two largest mammoth species, standing 12 to 18 inches taller than today's African elephant, its largest modern descendant.
Swiatovy said the results of the museum analysis won't be known for another three to four weeks. Meanwhile, Andrew Carroll and Thomas Smith say they plan to spend a lot more time in the creek, looking for other fossils.