Anybody know what this is?

I imagine it was some sort of roadside business, gas or food or whatever, but I don't know exactly. And why the funny shape? Was it to look like an oil well, a windmill, a kiln, what? It's located about 5 miles west of Tucumcari on old Route 66, not far from the old swim park. There is another one, just like it, a few hundred yards away.

UPDATE: According to the good people at the Tucumcari Historical Museum, it's a pump house. I assume it was to pump water to the pool at the nearby park, which was quite large. More on the park soon.