Heppen, 1938 2 mi. W Oakley, 50 ft., Contra Costa County, Cal. June 21, The hills between Crockett and Martinez are gently rolling, resembling those around Sofayette and Walnut Creek both in vegetation and in topography. Exposed hill tops and sides (but for canyon bottoms) are grass-covered. In the canyons are live oak, occasional Calif. bay, buckeye, poison oaks, and a few rose thickets. Few areas were seen which would provide cover dense enough for wood rats. The range of hills to the northwest of Mt Diablo and Mard Creeks are entirely grass covered. No canyons with chaparral or trees were noted on the creeks' side of those hills. Curry Canyon, from the mouth apparently just about to its source, is pretty much the same. In more moist and sheltered areas are sycamore, maple (few), bay, buckeye (much), rose. Poison oak abundant; hazel not seen. The understory is covered with dry grass and leaf litter - poor picking for mammals. P. maniculatus would be there, but not abundant. Probably P. truei would be few. Adenostoma stands prevail on the upper slopes of Mt Diablo Peak - as east or S-facing and crests of slopes from about 2500 ft. on up.