Quast 1948 Journal 20 April 17 Cerro Prieto 30 ft 20 mi SSE Mexicali, Baja Calif. 9:15 P.M. Maximum temperature today about 1:00 P.M. was 100 F. A breeze blew all afternoon blowing quite hard around 5:00 P.M. Cerro Prieto is a volcanic cone built up of large piece of dark volcanic rock. At the top is a cone elliptical in shape of about 150 x 200 yds. The rim is from 50 to 200 ft above the cracked mud floor of the cone and very irregular in outline. It is about 200 ft at its highest point above the valley floor. The walls (slopes) of Cerro Prieto are very rough and contain very little soil if any, small amounts of soil being present on the rim with a type of bunch grass growing in scattered patches in it. Cracks and small caves + cramies are present on the outside slope and also on the inside walls of the crater. The mountain is elliptical in shape and guessed at about 5 mi diameter. The rocky slopes are bare of vegetation. Large numbers of large bats (Macrotus?) were seen flying from the mountain at 7:30 P.M. (sunset) and the smaller Pipistrellus were seen feeding low among the mesquite about 15 min later. Two small squirrels were seen feeding in sandy roadway 100 yds west north of camp