This is an alternate descent from the Crest that drops down the WEST / Pacific side of the Continental Divide. This is a long 10-mile descent that crosses Agate Creek seemingly dozens of times, so it's best ridden late in the season.
While not as gnarly as other descents off the crest such as Green's Creek, Agate swoops and flows with astounding corners, jumps, and berms, forcing you to whoop and holler like a mad man on the way down! Thanks to this trail's remote ending and the work that it takes to shuttle it, when you drop into the more moderately rolling creek bottom (complete with a few climbs) you'll feel totally isolated from the world and in the wilderness. However, coming across a few wrecked vehicles that flew off the highway years ago will remind you that there's a major mountain pass just a few hundred feet above you.
Monarch Crest
http://www.singletracks.com/item.php?c=1&i=9046