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stones are fire-cracked rock resulting from stones used to heat or boil water; heated stones <br />were dropped directly into water containers of skin, basketry, or pottery. Boiling stone <br />remnants exhibit a particular kind of fracture called the “Hackley fracture” (also known as a <br />jagged fracture), which is sharp-edged and uneven. They are most often found in thermal <br />features termed “rock-filled hearths” because boiling stones were commonly placed back on <br />hearths reheated and used again; or once used were placed on the thermal features to retain <br />and radiate heat. <br />Due to various natural site formation processes, rock-filled thermal features can either <br />be covered or deflated. If the matrix around a thermal feature is deflating, the fire-cracked <br />rock can scatter to a point that can appear to double or triple the size of the original thermal <br />feature. They are usually identified by the lack of in situ burning, suggesting the burned and <br />fractured rock is a product of secondary deposition. These are often classified as thermal <br />features, but may be the remnants of a variety of cultural processes, including not only re-use <br />behaviors but also scavenging, maintenance, redistribution (through human or animal <br />trampling), or by natural, site formation processes (Petraglia 2002). <br />Burned rock middens, which are piles – or deflated piles – of fire-cracked rock, often <br />exceed several tons of material. Relatively little research has been devoted toward <br />understanding the function of such features. These middens may represent the remains of <br />roasting pits or earth ovens used in cooking bulbs and other plants (Doleman 1996). <br />Additionally, “archaeologists are beginning to do more with ethnographic descriptions <br />and experimentation...” (Reed and Metcalf 1999:81, 82). For instance, Stiger (1998:65) <br />experimented with the heat-output of four feature types at the Tenderfoot site and Francis <br />(2000:5) went so far as to calculate the potential volume of camas and biscuitroot that could <br />be processed in a large cobble filled feature at 48SU1002 in the Upper Green River Basin of <br />Wyoming. Thompson and Pastor (1995:91) also experimented with volume calculations for <br />slab-lined features in southwest Wyoming and determined that the vast majority ranged from <br />40 to 60 liters. This 40 to 60 liter subset contained features dating from the Great Divide <br />(7750-5600 BC) through the Uinta (1-1400 AD) phases. A second cluster of features had <br />calculated volumes ranging from 80-150 liters; the majority of these features dated to the Opal <br />phase (5600-3400 BC). Two extremely large (268.6 and 285.6 liters) were noted both dating <br />to the Pine Spring phase (3400-1450 BC). <br />Notably, over time, the surface and subsurface assemblages of sites are influenced by <br />natural and human forces that alter the horizontal and vertical distribution of artifacts, change <br />the frequency of artifact classes, affect the condition and preservation of the artifacts, and alter <br />the form and content of features. As soon as a piece is discarded, it is influenced by <br />compaction by the occupants of the site. In general, artifact assemblages are affected by post- <br />depositional processes that tend to move larger pieces toward the surface while smaller pieces <br />are sifted to the lower soil levels. Additionally, artifacts continue to be sorted differentially by <br />erosional/depositional influences and animal/human disturbance acting on the soils. One of <br />the most influential environmental forces is frost heave (Lewarch and O'Brien 1981:297, 308). <br />51