Proboscidean Tracks

Middle Miocene Barstow Formation--14.8 Million Years Old

Fossil Bone Basin, Mojave Desert, California

A year 1969 scientific excavation of two proboscidean tracks (large circular depressions in right half of photograph) from the middle Miocene Barstow Formation, preserved on the bedding plane of volcanic tuff radiometrically dated at 14.8 million years old--hardened pyroclastic material deposited into clear lake waters whose normal freshwater alkalinity was interrupted on occasion by evaporative periods and enormous quantities of volcanic ash ejecta which, eventually reworked by erosion and redeposited as firm mudflats, provided a perfect medium (analogous to wet concrete) to preserve the trackways of horses, camels, pronghorns, gomphothere proboscideans, and bear-dogs. The trackways are now found along the tilted and folded bedding planes of those lithified volcanic tuffs. Photograph from a specific scientific paper.

Here is the same proboscidean footprint near the top of the year 1969 photograph, above, as observed on September 11, 2010--now re-assembled and on display in a museum. It's the large circular depression situated at lower right, preserved on a bedding plane of volcanic tuff from the middle Mioence Barstow Formation, a tuff radiometrically dated at 14.8 million years old--hardened pyroclastic material deposited into clear lake waters whose normal freshwater alkalinity was interrupted on occasion by evaporative periods and enormous quantities of volcanic ash ejecta which, eventually reworked by erosion and redeposited as firm mudflats, provided a perfect medium (analogous to wet concrete) to preserve the trackways of horses, camels, pronghorns, gomphothere proboscideans, and bear-dogs. The trackways are now found along the tilted and folded bedding planes of those lithified volcanic tuffs. Photographed on September 11, 2010, by an individual who goes by the cyber-name coolislandsong24.

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