The trail across Palo Verde National Park was mostly a joy to ride, but when we hit this section of clay mud it became completely impassable. My track is to the right of Sue, but I was soon walking my bike as well. About where I was standing to take this picture the marsh closed in on both sides, the mud deepened and we spent over an hour traversing the next couple hundred meters carrying first our bikes then our panniers through knee-deep muck.