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1100318 R0T0 0811 JRW1 21 <br />The Precambrian age Pikes Peak Granite, designated Ypp on the geologic map, is exposed at the <br />ground surface along the western margin of the Permit Area. The Pikes Peak Granite consists of <br />pink to reddish-tan, medium to coarsely crystalline, granite or quartz monzonite. The unit is <br />highly weathered, fractured and jointed. Data from geophysical surveys performed by <br />MicroGeophysics Corporation (MGC) in 1998 indicate that the thickness of the surface layer of <br />highly weathered Pikes Peak Granite west of the quarry highwall is 10 to 34 feet in the surveyed <br />areas, with moderately weathered granite present below this layer. The interface between the <br />highly and moderately weathered granite is generally subparallel to the ground surface.50 <br />Surficial exposures of Pikes Peak Granite are limited to areas west of the Rampart Range Fault, <br />which juxtaposes the granite against the younger Sawatch and Manitou Formations to the east. <br />The Pikes Peak Granite is also interpreted to lie at depth beneath the sedimentary deposits <br />within the quarry proper, as shown on cross sections A-A' through H-H' (Appendix 39). Where <br />encountered at the bottom of boring EXC-2 on the floor of Area H (see the geologic map, <br />Appendix 39), the Pikes Peak Granite was extremely strong and resistant to coring. <br />East of the Rampart Range Fault, the Pikes Peak Granite is overlain by the basal quartz <br />sandstone member of the Sawatch Formation (Upper Cambrian age), designated as unit s Q on <br />geologic cross sections A-A' through H-H' (Appendix 39). The basal member of the Sawatch <br />Formation consists of massive, friable, fine- to coarse-grained sandstone with occasional silty <br />sandstone beds. It is typically white to locally black, with red-brown silty sandstone layers. <br />The basal Sawatch Formation measures approximately 30 feet in thickness in the quarry area. <br />The unit is only exposed at the surface in a canyon at the north end of the quarry, where it forms <br />prominent cliffs up to about 30 feet in height. <br />The basal member of the Sawatch Formation grades upwards into the fine-grained upper <br />member of the formation, s. This unit consists of finely laminated sandstone and siltstone with <br />occasional clay beds. The upper member of the Sawatch Formation measures approximately <br />40 feet in thickness. It is predominantly brick red in color but is also variably brown, green, <br />yellow, black and white. An interval of spaced clay beds are present in the upper part of the <br /> <br />50 MicroGeophysics Corporation, Final Report - Seismic Refraction Survey, Colorado Springs, Colorado, <br />August 18, 1998 (Appendix 40)