[meteorite-list] Should Calvin Crater be recognized as a confirmed Impact Crater?

[Robert Beauford]

After quite a bit of thought and research, I've demoted Calvin crater, on my impactcraters.us website, to an unconfirmed impact structure.  This contradicts the PASSC listing, and I think that the later should be considered the authoritative source.  Even so, I am responsible for building my listings according to the best reading of the literature that I can accomplish.  I'm posting this specifically to invite argument or disagreement with the decision - or agreement if appropriate.  I cannot find, anywhere in the literature, any reference to unambiguous or current widely accepted indicators of a hypervelocity impact event.  While the morphology is compelling (and this is, in fact, the guts of the past argument for Calvin), there are many structures with compelling morphology - and this is simply not a valid basis for inclusion with out further evidence.  The PASSC database does not typically include such structures.  A partial listing of the
 literature is present on the page, with links to most of the related papers.  http://www.impactcraters.us/unconfirmed_impacts/calvin_michigan  I'd be grateful if folks pointed out other related literature or challenged/supported my thinking.  In short, I'd like a sanity check.  If it is more convenient to engage the discussion on the facebook group, feel free.  I will follow the question in both places.  I have cross-posted this question there: https://www.facebook.com/groups/432433606804823/
Thank you, and best regards, 
- Robert