Bison bone?

I found this bone in a creek bottom. I know another person who found an identical piece in the same creek bottom. He swears his bone is fossilized that that it's a tooth. I don't think his or mine are fossilized and I think the bones are from a cow since there are cattle in the area and there are other cattle bones scattered about. After intensive searching with Google, the only thing I can find that's similar is always labeled as bison.  If this is indeed from bison, there are several possibilities as to the age of it. I've read that it takes 10,000 years for a bone to fossilize. And there haven't been any bison in this area in at least 130 years and if the bone is from the 1800s, it should have disintegrated by now. And some of the pics of similar bison bones have teeth intact. This piece actually is a bone section that held teeth but is not in itself actual teeth. If I can ever run into a veterinarian, maybe I can get a concrete answer. Until then, the mystery continues.

Petrified wood and flint

A nice blade portion I found awhile back in the bottom of a creek bed:

Copperas Creek flint:

Colorado River flint:
I'll post pics from the daytime later for better detail

Gryphaea Arcuata (Devil's Toenails)

Gryphaea Arcuata, also known as "Devil's Toenails" and sometimes "Texas Toenails", are fossilized extinct oysters that lived in the mud on the ancient sea floor. These are common worldwide and are very common in Comanche County, Texas if you know where to look.

10-27-2012 finds

Nice piece of a knife blade or spear point.

Crinoid

Fossilized oysters are very common around here since Texas was once almost completely covered by sea.

Bois d' Arc/Osage Orange - big crop this year

Petrified wood burl?