Emporia Formation

The Emporia Formation, also referred to as Emporia Limestone, is a Late-Carboniferous geologic formation in Kansas, extending into Nebraska, Iowa, Missouri, and Oklahoma.

This formation's members are, top to bottom,
 * Elmont Limestone, named for Elmont, Kansas (Beede, 1898)
 * Harveyville Shale, named for Harveyville, Kansas (Moore, 1936)
 * Reading Limestone, named for Reading, Kansas (Moore, 1936)

While the Elmont Limestone member is generally less than 3 feet thick (1 meter), it can be as thick as 15 feet (5 meters) and as thin as 12 inches. As thin as that, it is particularly resistant and forms multiple waterfalls in southern Riley County, including Pillsbury Crossing.