In the Big Horn Basin in Wyoming is our are of Wasalch deposits about 100 miles long and averaging about 40 miles wide where the strat are well exposed and are weathered in to the cahracteristic bad land forms so favorable for palaeontological explorations.  Dr. J. L. Worthman, their connected with the American Museum of the American Museum of Natural History, visted this region in 1896.  Through facilities for travel and exploration were not their so favarable as they are now,  yet he was successful in obtaining about three hundred specimens of fossil mammals, which added much