The Marble Mountain Wilderness lies within the Klamath Mountains west of Fort Jones, California.  This particular section b/w Black Marble Mountain & Marble Mountain contains a vast region of marble karst, w/ many channels & sinks of sculpted rock in solution leading down to vertical pits & cave entrances.  There are at least 150 known cave entrances within the karst, the largest is Bigfoot Cave w/ about 12.4 miles of known passages & a depth of 1,205 feet, which is more than Oregon Caves to the north.  I took this in a channel that still had a snowbank covering & cooled off underneath, watching meltwater trickle alongside the carved marble as it descended into darkness ultimately reaching a cave system below.  The geology of the Klamath Mountains is among the most bizarre & intriguing in North America.