Quast 1948 75 Journal May 22 Buena Vista, 25-½ ft, 23°35'N, 109°41'W, Baja California Visited a mountain full of caves this afternoon. Its name is Cerro Agua Amarga and it lies about 4 miles S.E. of the school. From the school, looking S.E., three mountains are visible, the tallest one being on the right of the other two. The hill containing the caves is the center one. The caves occur in sedimentary strata that run through the hill and their maximum depth probably does not exceed 75 feet. Most of them have wide mouths and are spherical within, the surface of the being pitted by innumerable concavities about 3 inches wide and as deep. We investigated all the caves we could find on the hill and found bats in only two of them. The first cave containing bats was about half way up the hill on the N.W. side and was about 75 feet deep, two small rooms being present one in back of the other. The ceiling was concave in both rooms and about 10 feet high. The stench of guano filled our noses the moment we stepped into the cave. About 300 bats were in the cave, all being Macrotus californicus except one 'Lepto- mycteria' (?). The other cave containing bats was near the top of the hill and also on the N.W. side. It was found to contain only Macrotus califor- nicus and none were taken.