I'm a great, if not uncritical, fan of the Ives Second Symphony.  I've
read that the opening is a nearly direct quote from Brahms, but I can't
place it.  My familiarity with Brahms is fairly good but if this theme
is really by him, it's something I've managed to miss.

Can anyone enlighten me?

Richard, who invites you to visit his Web site at http://opuspocus.ca