This photograph was taken in northern Mc Kenzie County just south of Lake Sakakawea and due north of the town of Arnegard. The Arikaree caprock of the Killdeer Mountains consists of tuffaceous sandstone and siltstone that is interbedded with thin layers of freshwater carbonates.
There is approximately 500 million tons of ash in a 4,000 acre area around Linton. The Marmarth Ash consists of approximately 6 feet of unaltered (white) tuff which is bounded by bentonite (gray). The most well known tuff deposit is the Linton Ash which has been actively promoted for a period of twenty years but has undergone little development. E., 1962, Investigation of pozzolanic properties of the Cretaceous volcanic ash deposit near Linton, North Dakota: North Dakota Geological Survey Report of Investigation No. The Linton Ash is well exposed in the hills north of the town of Linton in Emmons County. The Laetoli footprints are rare treasures in the record of human ancestry.
They are fossils captured in volcanic rock that can be given an absolute date."Absolute" dating means finding a specific age for an object.