By Jeremy W. Koch

Archaeologists excavating Native American campsites buried beneath the I. P. Morris Co. machine shop building in Philadelphia recently discovered the circular cluster of fire-cracked rock pictured in Figure 1. This precontact pit feature, measuring 1.2 meters in diameter, contained charcoal and several layers of river cobbles that had been cracked and fractured in situ from intense heat. The size, spatial arrangement, and contents of the feature suggest that the bed of fire-cracked rocks may have functioned as the heating element of an earth oven.