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G. <br />I <br />• soil and bedrock. The total thickness of sediments increases <br />~' from about 35 feet near boring BH-108 to over 75 feet near <br />.the mouth of the canyon. The major stratigraphic units within <br />~ the area explored can be characterized as follows: <br /> 1. Fill: The fill consists primarily of silty fine to <br /> coarse sand with variable amounts of gravel and con- <br /> struction debris. Locally extreme variations may be <br /> encountered such as in test pit TP-4 where some 6 <br /> feet of coal fill was found. The density of the fill <br />S is quite variable but is generally medium-loose to <br /> medium-dense based on average penetration resistances <br /> of 10 to 20 blows per foot during samplings. The <br /> deptFi of the fill was generally very difficult to <br /> determine even in the test pits since tl~e underlying <br /> colluvium/alluvium was essentially identical in com- <br />{ position. The depth of Che fill appeared to range <br />• from less than 5 feet to over 20 feet while aver- <br /> aging about 10 feet. These fill limits shown on the <br />l exploration logs are only approximate, based on subtle <br /> variations in density and composition. The fill ap- <br /> pears to thin toward the east and toward the north- <br /> south limits of the canyon. <br />l 2. colluvium/Alluvium: A thick sequence of colluvium/ <br /> alluvium underlies the fill and extends to the top <br /> C of the residual soil. The material is quite <br /> heterogenous and appears to exhibit little lateral <br />( continuity except near the mouth of the canyon where <br /> the explorations showed some evidence of layering. <br /> ( The deposit is composed predominately of silty fine <br />L to coarse sand with varying amounts of gravel size. <br /> rock. Locally, a major portion of the deposit is <br />`- composed of sandy silts and clayey silts. These <br /> <br />