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'T . <br />• <br />fine-grained soils appear to occur more as in- <br />clusions than continuous layers. The bottom of the <br />colluvium/alluvium appeared to increase from about <br />30 feeC in the vicinity of borings BI1-103 and <br />BH-108 (up valley) to over 80 feet near the mouth <br />of the canyon. Althougi~ it could generally be in- <br />(erred by changes in penetration resistance, the louver <br />limit of the sequence was often difficult to ac- <br />curately determine as it grades into residual soils <br />and/or weathered rock. <br />Based on a careful evaluation of the sample penetra- <br />tion resistances, there appears to be a change in <br />the overall density of the colluvium/alluvium se- <br />quence west of boring BH-104. East (up valley) of <br />` BH-104, the soils are generally moderately loose to <br />1 moderately dense with penetration resistances • <br />averaging about 10-15 blows per foot. {Vest (down <br />valley) of BH-104, the soils become loose to very <br />loose with penetration resistances averaging only <br />': about 4-10 blows per foot. <br />3. Residual Soil/{Veathered Rock: Residual soil and/or <br />weathered rock was encountered below the colluvium/ <br />alluvium. The material generally consists of <br />weathered shale, siltstone and sandstone in varying <br />degrees of decompositon. The borings generally <br />extended about 10 feet into the residual soil or <br />weathered rock before being terminated by very <br />( hard driving. <br />Our explorations were limited to the area within about 2,000 <br />f- feet of the mouth of the canyon. However; we can reliably • <br />1 <br />