To determine whether reduced vanadium ores could have been deposited by reduction from supergene quinquevalent vanadium solutions, the reducing capacity of fresh wood, wood degraded by long burial, and lignite was determined experimentally at temperatures of 120?? and 150?? in closed containers. A precipitate obtained by reduction of quinquevalent vanadium solutions with wood gave an X-ray pattern identical with a recently discovered low-valent vanadium mineral. The evidence indicated that deposition of reduced vanadium minerals by this mechanism is possible. ?? 1957.