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AET #94-1805 - Page 8 <br /> Disturbed Samples I S <br /> Some of the samples taken within the upper portion of the profile were disturbed materials taken <br /> from the flights of the auger. <br /> Sampling Limitations <br /> Unless actually observed in a sample, contacts between soil layers are estimated based on the <br /> spacing of samples and the action of drilling tools. Cobbles, boulders, and other large objects <br /> generally cannot be recovered from test borings, and they may be present in the ground even <br /> if they are not noted on the boring logs. <br /> Classification Methods <br /> Soil classifications shown on the boring logs are based on the Unified Soil classification (USC) <br /> system. The USC system is described in ASTM:D2487 and D2488. Where laboratory <br /> classification tests (sieve analysis and Atterberg Limits) have been performed, classifications per <br /> ASTM:D2487 are possible. Otherwise, soil classifications shown on the boring logs are visual- <br /> manual judgments. We have attached charts (Appendix A) illustrating the USC system, the <br /> descriptive terminology, and the symbols used on the boring logs. <br /> The boring logs include judgments of the geological depositional origin. This judgment is <br /> primarily based on observation of the soil samples, which can be limited. Observations of the <br /> surrounding topography, vegetation and development can sometimes aid this judgment. <br /> Water Level Measurements <br /> The ground water measurements are shown at the bottom of the boring logs. The following <br /> information appears under "Water Level Measurements" on the logs: <br /> • Date and Time of measurement <br /> • Sampled Depth: lowest depth of soil sampling at the time of measurement <br />