Geologic Contact

Lower Permian Riepe Spring Limestone-lower to middle Permian Rib Hill Sandstone

White Pine County, Nevada

A Google Maps street car perspective that I edited and processed through photoshop. A roadcut in White Pine County, Nevada, that exposes the precise geologic contact between the lower Permian Riepe Spring Limestone and the lower to middle Permian Reipetown Formation (formerly called the Rib Hill Sandstone). That prominent grayish ridge along the slope at roughly upper center-left lies in the Riepe Spring Limestone; the subdued rubble-strewn slope to left edge of photograph is the overlying and geologically younger Riepetown Formation (which directly underlies the middle Permian Arcturus Formation). The Riepetown is dominantly around 1,100 to 1,200 feet of yellow-gray siltstone and sandstone, with occasional interlayered beds of yellowish-gray dolomite and limestone. A coarse-grained medium-gray bioclastic limestone occurs at the base, near the contact with the underlying Riepe Spring Limestone. The Reipetown yields locally abundant conodonts (minute tooth-like structures, unrelated to modern jaws, that helped process food in an extinct lamprey eel-like organism) fusulinids, bryozoans, pelecypods, and various invertebrate tracks.

Return to: Fossils Along The Loneliest Road In America