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• At the top of the slide in the area of test borings No. 1 and <br />No. 2, a red, sandy, clay was encountered at approximately the 15 <br />and 18 foot levels respectively. This red sandy clay was extremely <br />wet which is presumed to be the failure surface of the slide. In <br />test boring No. 3 wet zones were present near the 3 and 12 foot <br />levels. <br />The location of each soil encountered in the test borings are <br />indicated on the test boring logs presented in this report. <br />The failure surface of the slide was evident in test borings <br />No. 1, No. 2, and No. 3 at the 15, 19, and 4 foot levels <br />respectively. No failure surface or water was encountered in test <br />boring No. 4. The lack of a failure surface in test boring No. 4 <br />indicates that the slide is confined to the area that can be <br />identified visually. No further instability is expected below the <br />toe of the slide. <br />SITE CONDITIONS <br />• As expected, the drilling, visual observations, and subsurface <br />investigations performed within the slide area showed a variability <br />of materials. The materials varied from a deposit of primarily <br />clays, cobbles and boulders, and weathered shale, which was <br />overlain by a variable thickness of colluvial, gravely clay, <br />material. However, the deposition of the colluvial materials and <br />the relative conditions created through past instability of the <br />slope area and past man-made disturbances made it difficult and for <br />the most part impossible to determine the difference between fill <br />and colluvium. The colluvium and fill materials were underlain by <br />interbedded sandstones, claystone and shale, varying in depth, at <br />the top of the slide, from 16 to 48 feet. Groundwater conditions <br />within the slide area consisted of two contacts, the upper one <br />being at the slope failure plane, and the lower one being at or <br />near the colluvium bedrock contact, with a layer of low permeable <br />clay between the two water surfaces. <br />• <br />21-5 <br />