Fire Broken Rock results from plunging super heated rocks into water to cause the water to boil.  Native people utilized this technique for cooking foods and for extracting fats and oils.  The rock used as the Salmon Beds is likely derived from the east bank of the river where glacial or post-glacial gravel deposits are exposed in the bank.  Without human intervention the rocks exposed on the east bank could not have been transported to the west side of the river.  Most of the rock utilized for stone boiling were roughly fist sized.  Most of these were quartzites or silicified siltstones.  The large amount of fire broken rock recovered from the Salmon Beds indicates that food processing was a major activity at the site.  Extensive cooking or boiling of fish may be the reason so few fish bones were recovered at the site.  Cooking or boiling of fish bones may have softened or altered them so that they rarely survived.

A total of 127.775 kilograms of fire broken rock was recovered in the excavations.  Table 5 shows that fire broken rock was recovered in 15 units for an average of 8.518 kilograms of fire broken rock per 1 meter square.  Units 8n1e, 8n0, 7n0, and XU2 contained the largest amount of fire broken rock (Figure 28).  Fire broken rock was most commonly found in level 8 (35-40 cm) followed by levels 4 (15-20 cm), 3 (10-15 cm) and level 2 (5-10 cm)(Figure 29).

TABLE 5:  WEIGHT OF FIRE BROKEN ROCK