The 3-volume edition of THE JOURNALS OF ALF DOTEN, edited by Walter Van
Tilburg Clark (Univ. of Nevada Press, 1973) features Doten's entry for

Sunday, March 6, 1864 - "J D Winters introduced me to "Mark Twain" (V 1, p.

This appears to be their first meeting which took place in Como in
March 1864 and after Clemens had already adopted the pen name.

There are other entries for Twain throughout the edition of
JOURNALS and the set does include Doten's 1899 stories from NEVADA MAGAZINE
in an appendix.