Heene, H. 1991 April 19 Bienes Regional Park, Contra Costa Co., California Today I saw a mountain lion! Wendy Roberts and I rode our mountain bikes from the Bear Creek Rd. entrance parking lot east up Old Briones Rd. Trail. At x/1230 h, x/1200' el., x 2/3 up the long winding slope to Briones Crest I sized and sat beside the dirt road while Wendy rode to the top. She returned shortly and we sat in the grass, eating sandwiches and talking. At x/1240 h I suddenly saw part of a red-tan animal disappear in shrub vegetation on the hillside SW of us and across a ravine, perhaps 100 m away. I remarked it looked like a carnivore, but for a couple of minutes we couldn't get a good view and speculated unconvincingly about a badger or racoon. Then as the animal moved out into view and leisurely traveled in irregular direction over the slope, we saw its telltale form and black-tipped tail. The cat moved to the horizon, slope of the hill, looked at us, disappeared, reappeared and again looked at us, then walked up the hill on the horizon and disappeared behind trees. We saw it for x 5 minutes and identification as Felis concator was certain. We thought the cat seemed to be searching in vegetation - the hill is fairly open, covered in green grass, with scattered shrubs and small trees. The cat definitely looked at us but never seemed alarmed. Knowing of several recent fatal attacks on humans in the U.S., we were