Yep, I agree with TheWoodsman, Osage orange is also known in Texas as Bois d'arc.

Since you (sabre500) and I are from Texas most of our wooden fence post are Mesquite, Oak, Cedar or Bois d'arc. What I see in your pictures looks like Osage Orange (Bois d'arc).
I've got a question for TheWoodsman or anyone else that wants to chime in; Does Black Locust, up north, grow with thorns on it?:blink: It does in Texas. When you find one, here in Texas, it has wicked looking thorns on it some of them may be up to 4 inches long. I'd hate to have to cut one down with a chain saw! ! !:thumbdown: Ouch ! !