Systematic collection from these fluvial exposures has produced a faunal assemblage of extraordinary richness — the bones of woolly mammoths, horses, bison, caribou, lions, bears, and dozens of other species, preserved in the frozen sediment for tens of thousands of years and released by erosion into the river banks.

Among the Old Crow specimens, earlier researchers identified a bone that they claimed showed evidence of human modification — a caribou tibia that appeared to have been worked into a fleshing tool, a scraper used to process hides.

The Old Crow caribou tibia was initially dated to approximately 27,000 years ago, and the claim that it showed evidence of human modification generated significant controversy in the 1970s and 1980s.

Subsequent reanalysis of the Old Crow specimen — including both taphonomic reexamination of the modification and re-dating using improved methods — produced results that were much less compelling than the initial claims.