There is info on Clemens's association with John Ross Browne in
several volumes of MARK TWAIN'S LETTERS (University of California
Press).  This same info is also available in the online letters
database at:

http://www.marktwainproject.org

To bring them up in the letters database, search on:

J. Ross Browne
John Ross Browne
Ross Browne

Clemens did comment in a letter to his relatives about Browne's Washoe
writings in Harper's.  And he did stay overnight with Browne when
Clemens passed through Oakland on a lecture tour in 1866.  The notes
to these letters make clear that Browne and others believed YUSEF
influenced Twain's writing.

Barb