What was Nick's initial description of Gatsby?

From the text:

I had expected that Mr. Gatsby would be a florid and corpulent person in his middle years.

I would have accepted without question the information that Gatsby sprang from the swamps of Louisiana or from the lower East Side of New York. That was comprehensible. But young men didn’t — at least in my provincial inexperience I believed they didn’t — drift coolly out of nowhere and buy a palace on Long Island Sound.