The deposits on the floor of Mummy Cave, overlooking the Shoshone River Valley, are 30 feet thick and have been dated as far back as 9000 years before the present. The first deposits are from the age of the Big Game Hunters, before any evidence of a more varied diet and lifestyle can be found. Later deposits show evidence of a more generalized lifestyle, including the use of plant gathering, fishing, hunting of small animals such as rabbits and the use of baskets in these activities. Large notched projectile points are characteristic of this period, referred to as the Archaic, beginning about 7000 years ago in the area of Mummy Cave.
Later developments included the development of horticulture (farming), use of the bow and arrow, development of pottery, and use of more substantial housing. In Mummy Cave, this era is seen in the fragments of bows and arrows. However, in the 30 feet of deposits on the floor of the cave, only the top 12 - 15 inches of deposits contain pottery fragments. Apparently pottery came very late to the Yellowstone area.