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5.8:PALEONTOLOGICAL RESOURCES <br /> mapped in the vicinity of the LEC,and given the project's location at the toe of the <br /> Mokelumne River alluvial fan the Riverbank is expected at depths far exceeding what <br /> construction related excavations would reach (e.g. >80 feet;Atwater et al.,1986). <br /> The surface of LEC is entirely occupied by previously disturbed sediment and artificial fill <br /> (sediment transported from elsewhere or fill that is a mix of materials). The depth to <br /> undisturbed sediment is variable from place to place but, generally in this area,extends at <br /> least to the bottom of the"plow zone' or about 4 feet below the surface. This material has <br /> no potential to yield scientifically important materials,and therefore possesses no <br /> paleontological sensitivity. <br /> 5.8.3 Environmental Analysis <br /> The environmental impacts on paleontological resources from both construction and <br /> operation of LEC are presented in the following sections. <br /> 5.8.3.1 Paleontological Resource Significance Criteria <br /> In its standard guidelines for assessment and mitigation of adverse impacts to <br /> paleontological resources,the SVP (1995) notes that an individual fossil specimen is <br /> considered scientifically important and significant if it is: (1) identifiable, (2) complete, <br /> (3) well preserved, (4) age-diagnostic, (5) useful in paleoenvironmental reconstruction, <br /> (6) a type or topotypic specimen, (7) a member of a rare species, (8) a species that is part of <br /> a diverse assemblage, or (9) a skeletal element different from, or a specimen more complete <br /> than,those now available for that species. For example,identifiable land mammal fossils are <br /> considered scientifically important because of their potential use in determining the age and <br /> providing input to paleoenvironmental reconstructions for the sediments in which they <br /> occur. Moreover,vertebrate remains are comparatively rare in the fossil record. Fossil plants <br /> are also important in this regard and, as sedentary organisms,are actually more sensitive <br /> indicators of their paleoenvironment and,thus,more important than mobile mammals for <br /> paleoenvironmental reconstructions. For marine sediments, invertebrate fossils,including <br /> marine microfossils,are scientifically important for the same reasons that land mammal <br /> and/or land plant fossils are valuable in terrestrial deposits. The value or importance of <br /> different fossil groups varies depending on the age and depositional environment of the <br /> stratigraphic unit that contains the fossils,their abundance in the record, and their degree of <br /> preservation. <br /> Using the criteria of the SVP (1995) and the sensitivity ratings provided above,the <br /> significance of potentially adverse impacts of earth moving on the paleontological resources <br /> was assessed. Any unmitigated impact on a fossil site or a fossil-bearing rock unit of high or <br /> moderate sensitivity would be considered significant. <br /> 5.8.3.2 Paleontological Resource Impact Assessment <br /> The significance of potential adverse impacts of project-related activities on the <br /> paleontological resources of each stratigraphic unit anticipated to be present at the project <br /> site is provided in this section. This assessment includes the entirety of the project area. <br /> • Artificial Fill and Previously Disturbed Sediment-Construction-related excavations <br /> within artificial fill or previously disturbed sediment will not result in any adverse <br /> SAC13713221082340008(LEC_5.8_PALEORES.DOC) 5.8-7 <br />