Aven Nelson's field book dated 1897, containing records 2851 to 3500. This book actually contains: 2851-2874, 2904-2949, 3146-3458, 4501-4509 (Elias Nelson); 3459-3500, 4144-4284 (Aven Nelson); 4285-4309 (W.C. Knight). The inside front cover says Book 5a. Observations were made throughout Wyoming.
Manuscript originals available at the University of Wyoming.