Photo Sunday
Walnut Bush?

My sister and I went bicycling today out on a trail by the river and we found this odd unidentifiable plant. At first we thought they were walnuts but most the trees with these things were squat and looked more like bushes which does not describe the walnut trees I remember. Anyone recognize it?

I cut it open the unidentified fruit or nut open with my key but it didn't help to reveal the mystery. It was rather soft for a nut but possibly wasn't ripe.

Here's also a blurry picture of a rattlesnake because my sister's smart phone doesn't have much of a zoom and there was no way we were getting closer.