Woodson Cty., Kansas Riley Cty., Kansas Pike Cty., Arkansas Colorado Plateau (Mule Ear, Moses Rock, Garnet...Fayette County, Pennsylvania; 3 Elliot County, Kentucky; 4 Norris, Tennessee; 5 Crittenden County, West...Illinois; 7 Avon, Missouri; 8 Pike County, Arkansas; 9 Riley County, Kansas; 10 Navajo-Hopi Province;...Murfreesboro, Pike County, Arkansas, and another non-diamondiferous one in nearby Cleveland County. They occur...downwarp of the Mississippi embayment, and the Pike County kimberlite is accurately dated as mid-Cretaceous |