Hafner, M.S 1974 Journal 13 June Mason Valley, 27 km S, 8 Km E Yerington, 1525 m, Lyon Co., Nevada. Approx 2:00 Pm. we arrived in Mason Valley (Atriplex association) and we drove over a very rough sandy road to the Walker River where we had a swim. The river was muddy, cool and very fast moving (approx 30 m wide at this point) The area nearby (where we swam) was planted in clover for dairy cattle and the marsh-like land made good habitat for the many ducks and magpies we observed. (John found an arrowhead on the walk from the car to the river! :) On our way back to the car John noted a very large (Redtail ?) nest high in a tree - we could not identify the tree type nor see any young in the nest from a nearby hill (we did not suspect young to be in the nest in mid-June). We returned to camp, noting a Collared-lizard on rocks nearby the road. Our setting out of traps was interrupted by 2 old men on who stopped their truck near camp and began what ended up to be a lengthy discussion over a couple of