May 31, 2011, Rio Grande between S. Fork and Creede, CO, 11:15 A.M. Wading river across from road to Creede which has a regular traffic flow. Came up out of river to get rid of some coffee and as I was pulling down chest waders, my Brittany charged up the hill and flushed a full grown mt. lion which had been hiding beneath/behind a bus just 60 feet away. Dog chased cat. I called dog back and waited a couple of minutes before climbing the short hill to the mesa above. Cat was walking slowly past my pickup a couple of hundred yards away and proceeded to stroll into the woods. Am told such close encounters are rare. I could have lived without the experience, thank-you.