This well-illustrated book is a fascinating two-part study of the mastodon-dominated, late Pleistocene fossil assemblages from two spring sites occuring along the Pomme de Terre River in western Missouri. Part I is a descriptive study of the fossil remains recovered from Trolinger and Boney springs. Part 2 is a synthesis of data directed toward an understanding of the events and conditions prevailing at the death, decomposition, dissociation, and burial of 31 mastodons (and other animals) at Boney Spring 13,500 years ago.