Early morning hike - did this as an out and back under gray skies. As you leave Garden Valley heading toward boulder canyon, the geology changes drastically and you walk through an area of dark gray/almost black rock. Even the dirt changes color, from the light tan you usually see to a much darker gray brown. You pass through hills on either side that are completely covered in large, black gravel. On your right is a tributary which looks like a black granite mini-canyon with a couple of pools along the way. Very pretty. I wouldn't have minded a bit of sunshine for those photos. On the way back, I could see it raining on and off just over the mountains all around Garden Valley as I walked through. Eventually, it found me, too. Hiked the last mile and a half in a gentle, intermittent rain. Wunderbar!