R. Zweifel April 23, 1951 Los Angeles County, Calif. 239 The hillsides surrounding the locality are in the juniper - piñon association. 5.1 mi., mouth of Base Mtn. Canyon, elev 3600' Ten Hyla arenicolor and one Rana boylii mucrosa , the latter from a well-shaded pool, were collected here. The plant associates are the same, except that Salix is added in the stream bottom and Arctostaphylos on the hillsides. 5.6 mi.) An LOX Coluber lateralis escaped here. Piñon - juniper association 7.6 mi., Sycamore Camp brand, 6 Rana boylii mucrosa were collected and at least that many more seen, both in large pools in the stream and in the shallower riffles. Water temperatures were 14.1°C and 17.2°C. Sycamore, alder, willow, cottonwood, Buckwheat in the canyon bottom. The hillsides are piñon - juniper. Poison oak in the canyon bottom was noticed first at this station. Most of the stream below this locality is not typical