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Page 8 Gco(agtcal reckxus rxG Site Conceptual Modet Report Project No 724 2 May 2,2006 ' units) extending to 23 feet bgs A thin, 0 5 foot thick sand to clayey sand unit is present at 24 feet bgs that is underlain by more fine grained units Silty sands, sandy silts or silts are present from 24— 27 feet bgs A thin, 1 foot thick sand to clayey sand ' unit is present at 27 feet bgs that is underlain by two feet of sandy units The remainder of the borehole encountered more fine grained units from 29 to 55 6 feet A soil sample from 37 feet bgs was identified as an olive, slightly moist, axed plastic ' clayey silt by the field geologist This data correlates well to the CPT log that shows the interval as a clayey silt to silty clay ' • CPT-2 The CPT log shows primarily fine grained units extending to the total depth of 67 feet bgs The log shows clays or silty clays to 8 feet bgs, then silty sand to sandy silt layers to 11 feet bgs This is underlain by fine grained units extending to 25 feet bgs A 0 5 foot thin sand to clayey sand unit was identified at 26 feet bgs, and again at 66 feet bgs The remainder of the borehole encountered more fine grained units from 26 to 67 feet bgs Soil samples from 35 feet bgs were identified as an olive, moist to wet, sandy clay with very fine sand grains by the field geologist This transitioned downward to an olive, moist, soft, clayey silt This data correlates fairly to the CPT log that shows the interval as clay ' • CPT-3 The CPT log shows primarily fine grained units extending to the total depth of 61 feet bgs Fine grained units are present from the surface to 26 feet bgs Two feet of silty sand to sandy silts are noted at 26 to 28 feet bgs and these are underlain by a very thin (<0 5 feet thick) sand to clayey sand layer The remainder of the borehole encountered more fine grained units from 28 to 61 feet bgs A soil sample ' from 35 feet bgs was identified as a brown, moist, firm silt by the field geologist The CPT log shows this depth to be silty clay to clay ' o CPT-4 The CPT log shows primarily fine grained units extending to the total depth of 82 feet bgs Fine grained units are present from the surface to 37 feet bgs Two feet of sand/silty sand to sandy silts are noted from 37 to 39 feet bgs The remainder ' of the borehole encountered more fine grained units from 39-to 82 feet bgs A soil sample from 38 5 - 40 feet bgs (with 12" recovery in tubes) was identified as a fine to coarse, dark grey, moist sand by the field geologist The CPT log shows this interval ' to be transitioning from the sandy units noted at 37 feet to clayey units at 40 feet Note The cross sections were developed using data gathered by different individuals utilizing different methodologies Therefore, they need to be looked at as one of several possible interpretations of actual site conditions ) ' GTI has completed cross sections depicting our interpretation of the subsurface- see Figure 3 for section locations Figure 4 Cross Section A — A' illustrates the geology trending from the northwest to the east of the site The diagram indicates that more sands are present below 65 feet bgs on site and below 50 feet bgs in the off-site location of MW-1091209 GTI's interpretation of the geology has shown sand units at 25 and 50 feet bgs as laterally continuous These units were not uniformly identified in the original boring logs for wells