Cross over it, and the Crystal is on asmall corner at the edge of a cliff.
Either kill or run past them until you see theone next to the repairable bridge.
Kill this one and the Crystal ison the hill up the path it was blocking.
When youreach the quicksand area, keep goingpast it and down the slopeonto the beach.
Continuenorthwest across the shallow waterto a section with light brownquicksand and several Saw Plants.
Getting the last Ancient Key is going to put you through the most difficult trials of them all.