Has anyone ever heard of the "Gentlemen's Riding Club" in New York City,
predecessor organization to the Riding Club, an elegant establishment with
stables for 300 horses built on East 58th Street in 1883?

I'm interested in the earlier club, specifically when it was founded and
what its membership requirements were, but none of my encyclopedic
references mention it and I don't know where to look next.

Any clues would be welcome.

Emily Leonard