P. PEARSON 1948 38 Jackass Hill, 5 mi. W of Sonora, Tulame County, Calif. Mar. 12 Left Berkeley 2:20 p.m. with Anita, Mary Koford, and Haves Gray, arrived Gray's cabin near Tuttletown 6 p.m. Caught two Myotis californicus in the cabin (δ and ♀) and several others escaped. Also one or Corynorhinus in the Gray mine tunnel (The Relief Mine). After supper visited 5 other good mine tunnels on Jackass Hill (Chilena Mine, Mark Twain Mine, etc.) Found one more lone Corynorhinus δ and a pair of Myotis californicus. These were mounted, one almost smothered by the other, and one was a δ and the other ♀. The vaginal region of the ♀ was bruised and the skin of flanks red (from scratching by δ?). The penis of the δ was considerably enlarged and reddish, looking somewhat bruised. More of the above specimens were torpid. Mar. 13 Drove to Mercer Cave, looking in numerous abandoned buildings on the way. The "tourist" part of the cave is electrically lit and the owner was reluctant to have us look in other parts or in other shafts. He didn't think there were many bats - if any. It is a limestone region. Also went to Moaning Cave, but the entrances have been bat-proofed. Stopped at the Denamore Mine near Moaning Cave. The caretaker there, Mr. Hill, told of a tunnel and stope at the Goodwin Dam near Knight's Ferry, where he used to dig bat guano and sell it. Drove there and found the place, a long tunnel with occasional heaps of guano and a large stope with much guano. Only one male Corynorhinus, δ in the tunnel.