The Extreme Ammonites of Fossil Hill, Pershing County, Nevada
In 1902 a scientist visiting Fossil Hill in Troy Canyon near South American Canyon on the eastern flank of the Humboldt Range near Lovelock, Nevada, discovered a remarkable fossil bed. James P. Smith noted: “… the hillside was literally covered with loose ammonites…”
Ammonites are the extinct ancestors of modern cephalopods that lived in the warm lagoonal waters of an ancient sea that covered much of western North America some 200 million years ago.
Among the specimens collected by Smith was an ammonite cast that measured 8.81 inches in diameter and another, although incomplete, was 10.25 inches in diameter and was described by Smith as “”largest and handsomest species of Gymnites known.” Smith concluded the diameter of a whole specimen may have been as much as 15.75 inches. The average diameter of ammonite casts from the area is a few inches.
See photos and more in The Extreme Ammonites of Fossil Hill updated March 13, 2014