cracks, rocks etc. that are available? at 12:30 pm: cloudy bright, no shadows: Schultze's thermometer in open: 19.6° In 40 mm shell lying on ground 21.6° Shallow sandy gravel (bulbs just buried) 22.4° Under feet rock 21.0° at 3:30 went back to Cuadroto the Cruz de Hueso 5 1/2 km. NE San Bartolo to camp overnight. Set 10 tension spindle and 20 thermos along the arroyo (a puffer tree about every 100 yards, 1 coña brava, fuchsia-like bushes, morning glory, lantana?, etc.). mouse tracks in one place. Anita set 30 mm. open along the arroyo dies, and those 20°. The valley floor seems to be of about 2 levels: a flat soft eartly sand about 20 feet thick about 20 feet above a hard mud flat into which some gulleys are cut. The hard surface seems to be a series of mud flows a few inches thick. In one place we could see the edges of 3 successive flows. Some of the flows have & parallel mud-cracks (not liquefied). Went pocketlighting at dusk but saw only 4 huge moths; at [7:30] went around the hard mud desert but not the soft, then at 7:30 went upon the soft central area to look for gasoz. Found seven. Following temperature data with Schultze's thermos (see right) gasol-air (4.2°) just under surface;