Not making a lot of progress on the American front. Found the Metaphysical Club, which is pretty much what the X Club would have been if you believe the downplay angles presented. There's been a book published (2001), so it's drawing new attention. Wiki book link. Harvard book link

There were only four members, and they don't seem to have conspired so much as collaborated. The book argues that their influence is not commonly appreciated. Probably true. William James was connected with quite a few celebs, and I notice more than a couple of evolution-pushers on the list.

I'll keep looking. It's seems possible that the American program was fairly decentralized at the time, and didn't consolidate until later on.

Dark Matter + Dark Energy = Dark Truth

"We find that such evidence demonstrates that the ID argument is dependent upon setting a scientifically unreasonable burden of proof for the theory of evolution." - Judge Jones Kitzmiller case
http://www.talkreason.org/articles/Falsify.cfm

"To Compel A Man To Furnish Funds For The Propagation Of Ideas He Disbelieves And Abhors Is Sinful And Tyrannical." - Thomas Jefferson

"And can the liberties of a nation be thought secure when we have removed their only firm basis, a conviction in the minds of the people that these liberties are the gift of God? That they are not to be violated but with his wrath?" - Thomas Jefferson