Upload & Sell: Off
Thanks for commenting Robin, NB and Bob.
The reality (most likely) is that the old outhouse was there in the first place, and then the land surrounding it became a source of dirt for some sort of construction- probably the highway department. Those guys had a sense of humor, and excavated around the outhouse, leaving it in place.
I'm sure more than a few people drove by and had a good laugh. I'm one of those who made a U-turn to take a pic.