[meteorite-list] Crater Wrong?

[E.P. Grondine]

Hi all - 

I have always read that Serpent Mound, Ohio was built on top of an impact rebound, but the other evening I was told that it was built on top of the center of a collapsed volcanic caldera. While functionally it does not make any difference, as I don't remember any shatter cones from it being offered for sale on the list, and I am wondering.

E.P. Grondine
Man and Impact in the Americas