Fossil Mammal Bone frags

[Niko]

I found these in gravel bar at a creek where i collect bottles but the thing is i live near portland oregon. Not florida or some place where ice age fossils are quite common. I have heard of mammoths and other ice age mammals being found in Woodburn and Yamhill(near Portland) but finding these was quite unexpected. Anyone familiar with the geology of the area out here? any other imput would be great.
Thanks

 

[Niko]

This is the only pic i could get before the camara battery died...I will try to take some more later.

 

[Niko]

Here is a bigger pic

 

[GuntherHess]

what made you conclude they were mammal bones?
are they truely fossilized or just preserved?

 

[Niko]

When I first found them I thought mammal bones made the most sense based on the location. A buddy of mine worked on a dig in Woodburn and he seemed to agree.

 

[capsoda]

Very Cool find. I would think there would be plenty of fossil remains in your area. Wyoming and Montana are covered with them and I know they are found in California and Washington too.