Devil's Canopy Cave

Devil's Canopy Cave is part of a karst hydrologic complex and has a small stream running into its entrance, which is a 10-meter-deep pit with several small skylights (see photo at left). The stream continues down a narrow twisting passage and then disappears into a sump. The cave is neither a den nor an effective natural trap. But an upper dry room near the end of the stream contains a bedded silt deposit that still fills much of the chamber (see photo below). In a pile of silt weathering from this deposit, mammalogist Joe Cook (on a trip with Jim Baichtal and Paul Matheus in 1993) discovered the incisor of a hoary marmot. Marmots do not live on Prince of Wales Island today and have not been found in any of the postglacial cave deposits. A radiocarbon analysis indicated that the incisor was at least 44,500 years old (a limitless date).

Dr. Heaton and Dave Love spent one day excavating at this cave in 1994. They filled mosquito net bags with large volumes of the soft, loose silt (see photo at right) and used the cave stream to wash these sediments inside the cave. Only the gravel concentrate was removed from the cave, and it was dried and searched for bone. A number of rodent remains were recovered including a marmot molar and a jaw and several bones of deer mouse (see photo below). They returned to the cave for two days the following year (with a crew of family and friends to do the screening) and began systematically excavating the in situ silt deposit in 5 cm intervals (see photos below).

With the help of Fred Grady and others, these one-day excavation trips continued each summer until 1998, and a total 83 gallon-size bags of sediment were processed. However, the hope of finding a rich fossiliferous layer within the bedded silt was never realized. Fossils were few, and no additional marmot parts were found. Several jaws of shrew were recovered from some pockets of reddish sediment in the ceiling, but it was unclear whether they were contemporaneous with the silt deposit or were younger, and they were too small for radiocarbon dating. Instead of pursuing this site further, attention was turned to On Your Knees Cave where a large Ice Age fauna was discovered.

Close-up view of part of the original bedded silt deposit in Devil's Canopy Cave (left), and a part of the bedded silt where a trench was excavated in 1995 (right).

Devil's Canopy cave is located close to the main road leading along the El Capitan Passage to the northern part of Prince of Wales Island (near Kushtaka Cave but farther from the ocean). Its location in the middle of a small stream valley does not reveal many clues to the origin of the bones. They may have simply been washed in from the surface by an ancient stream, or there may have been some kind of a den site from which the remains were transported by water. Not knowing the age of the bones, it is difficult to speculate how much glaciers have reshaped the landscape since their deposition or even what kind of climatic conditions prevailed when the animals lived.

© 2002 by Timothy H. Heaton