Snake

This morning when Josiah went to put some mail in the mailbox this is what he found in the road just down from our box.

You can see Josiah's shadow.

BTW it is still alive.

We're not sure what kind of snake it was (Josiah said it had about four lumps in it so it had just eaten something). It had a rounded head so it's not venomous, and it appears to be a grayish white color with black diamond shapes along its body. He didn't see the tail but figure that it's not a rattlesnake since its head was rounded and not diamond shaped.

Anyone know what kind of snake this is? (Sorry no closer images available)