1973 Apr 30 \frac{1}{2} mi. W. Horse Thief Spr, San Bernardino Co., Calif. Excelsior Mine Rd, and this continues TO Horse Thief Sprs. The road is heavily used by mine ore Trucks day and night, but is well paved as a result. My camp was by a U.S.G.S. marker, \frac{1}{2} mile East of the mine, just before a wash. A slope on the other side of the wash is covered with blotch bush and Salvia cernosa var pilosa. The soil was sandy, but the surface was well covered with small flat rocks (1" sq. or less). I set 61 traps on the gentle slope, most at burrow systems of the correct size for it-data. all at base of peach thorn - Lycium cooperi. Bad mix and oatmeal as bait. I set 9 traps in a less extensive sandy flat near camp, also dominated by blotch bush. In the afternoon there was a hail and rain storm, the air was cold and the wind blew. The night was calm and moonless, but the colder than the day - about 40° F, I guess. I caught 1 peromyscus monaxalates, 5 perognathus longiventris and 1 p. parvus in the hillside traps. I caught 2 P. longi- mentris and 1 Dipodomys microps in the 9 sandy area traps. Meal: It is a waste of time to trap for dipsos in rocky soil. Not much area is without rocks even in the flat by the camp site,