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City of Pleasanton—Hidden Canyon Residences and Preserve Draft EIR Geology, Soils, and Seismicity FirstCarbon Solutions 3.6-33 https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480016/EIR/3 - Draft EIR/21480016 Sec03-06 Geology.docx Monterey Formation (Tm) and an unnamed Miocene siltstone and clay shale (Tmc) formation. In addition, the UCMP Locality Search Online Database and records search conducted on March 25, 2025, did not identify any fossil localities within the project boundaries. However, vertebrate and invertebrate fossil localities have been uncovered within both the Claremont Shale member (or Formation) and the Monterey Formation (or Group) (Tm) in proximity to the project site and in the surrounding region. Although surficial deposits on most of the project site consist of colluvium and residual soils ranging from approximately 2-11 feet in depth, which have low paleontological potential, subsurface conditions also consist of high paleontological potential rock units from the Claremont Shale member (or Formation) and the Monterey Formation (Group) that have been associated with vertebrate and invertebrate localities in the geographic region. As such, excavations that intrude into the Claremont shale and Monterey formations (i.e., generally below 2 feet) during construction of the proposed project may directly or indirectly destroy a unique paleontological resource. This would constitute a significant adverse impact on paleontological resources. Thus, implementation of MM GEO-2a through GEO-2d would include the provisions required for the protection and recovery of paleontological resources. As such, with the implementation of MM GEO- 2a through GEO-2d, impacts related to damaging unique paleontological resources would be reduced to less than significant. Operation Potential impacts to paleontological resources are limited to the construction phase. No operational impacts are anticipated. Level of Significance Before Mitigation Potentially significant impact. Mitigation Measures MM GEO-2a Prior to the issuance of grading permits, the project proponent/developer shall demonstrate the retention of the services of a qualified professional Paleontologist as defined by the Society of Vertebrate Paleontology (SVP). The qualified Paleontologist shall prepare a Paleontological Resource Impact Mitigation Monitoring Program (PRIMMP). The project proponent/developer shall submit the PRIMMP to and receive approval from the City/Lead Agency. The PRIMMP will describe, in addition to industry standards and SVP standards, the level of monitoring required in the project area, qualifications of the Paleontological monitor for grading operations, and identification of personnel with authority and responsibility to temporarily halt or divert grading equipment to allow for recovery of large specimens. Furthermore, the PRIMMP shall provide direction for any fossil discoveries to be immediately reported, means and methods to be employed to quickly salvage fossils as they are unearthed to avoid construction delays, sampling procedures and protocol for collecting and processing sediments and specimens, fossil identification, and reporting and curation procedures to be employed. The report will include the paleontological records search conducted at the UCMP, pertinent exhibits, maps and reference procedures for reporting of findings.