Paleontological Technical Memorandum for the Lake Gregory Dam Rehabilitation Project, San Bernardino County, California

PALEONTOLOGICAL TECHNICAL MEMORANDUM FOR THE LAKE GREGORY DAM REHABILITATION PROJECT, SAN BERNARDINO COUNTY, CALIFORNIA

Prepared for: Aspen Environmental Group 5020 Chesebro Road, Suite 200 Agoura Hills, CA 91301

Authors: Courtney Richards, Kim Scott and Sherri Gust

Principal Investigator: Sherri Gust, Qualified Paleontologist

October 2014 Revised June 2015

Cogstone Project Number: 2861 Type of Study: Paleontological resources assessment Sites: None USGS Quadrangle: San Bernardino North 7.5’, Silverwood Lake 7.5’ Area: 28.08 acres Key Words: Mesozoic plutonic rocks, Holocene alluvium, granite, diorite, low paleontological sensitivity

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Lake Gregory Dam Paleontology Memorandum

TABLE OF CONTENTS

EXECUTIVE SUMMARY ...... III INTRODUCTION...... 1 PURPOSE OF STUDY ...... 1 PROJECT DESCRIPTION AND LOCATION ...... 2 PROJECT PERSONNEL ...... 4 BACKGROUND ...... 5 GEOLOGICAL SETTING ...... 5 STRATIGRAPHY ...... 5 MESOZOIC PLUTONIC ROCKS ...... 5 HOLOCENE ALLUVIAL SEDIMENTS ...... 5 RECORD SEARCHES ...... 7 PALEONTOLOGICAL SENSITIVITY ...... 7 CONCLUSIONS AND RECOMMENDATIONS ...... 8 REFERENCES CITED ...... 9 APPENDIX A. PALEONTOLOGICAL RECORDS SEARCH ...... 10 APPENDIX B. PFYC CRITERIA...... 13

LIST OF FIGURES

FIGURE 1. PROJECT VICINITY...... 1 FIGURE 2. PROJECT AREA ...... 3 FIGURE 3. GEOLOGY OF PROJECT AREA ...... 6

LIST OF TABLES

TABLE 1. PALEONTOLOGICAL SENSITIVITY RANKINGS ...... 8

Lake Gregory Dam Paleontology Memorandum

EXECUTIVE SUMMARY

The purpose of this study was to identify any possible paleontological resources that could be present in the Lake Gregory Dam Rehabilitation project area located in San Bernardino County, California. This study was requested by San Bernardino County to meet their responsibility as the lead agency under the California Environmental Quality Act (CEQA).

The proposed Lake Gregory Dam Rehabilitation Project consists of structural reinforcements to the existing dam. Four alternatives for remediation of the dam are under consideration: downstream stabilization buttress, cement deep soil mixing, stone column, and upstream asphalt facing alternatives. The downstream stabilization buttress is the preferred and State Division of Safety of Dams (DSOD) approved alternative.

The surface of the Project Area, including the borrow sites added in 2015, is mapped almost entirely as Mesozoic plutonic rocks. A small portion of Lake Gregory is mapped as Holocene alluvial sediments. Paleontological records searches of the Lake Gregory were conducted at the San Bernardino County Museum and in online databases and literature. All searches were negative for fossils within the Project. Further, it was determined that the geologic units of the Project area do not have potential for paleontological resources. Mesozoic plutonic rocks were ranked very low or PFYC 1 as they do not contain fossils due to the way they form. The Holocene alluvial sediments were ranked low or PFYC 2. Due to its young age, it is not sensitive for fossil resources.

Neither the record searches nor background research indicate any sediments sensitive for paleontological resources will be impacted by the proposed Project. No further paleontological work is required. If unanticipated fossils are unearthed during construction, work should be halted in the immediate vicinity of the find until it can be evaluated by a qualified paleontologist.

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Lake Gregory Dam Paleontology Memorandum

INTRODUCTION

PURPOSE OF STUDY

The purpose of this study was to identify any possible paleontological resources that could be present in the Lake Gregory Dam Rehabilitation project area located in San Bernardino County, California (Figure 1). This study was requested by San Bernardino County to meet their responsibility as the lead agency under the California Environmental Quality Act (CEQA).

Figure 1. Project vicinity

Lake Gregory Dam Paleontology Memorandum

PROJECT DESCRIPTION AND LOCATION

The proposed Lake Gregory Dam Rehabilitation Project consists of structural reinforcements to the exiting dam. Four alternatives for remediation of the dam are under consideration: downstream stabilization buttress, cement deep soil mixing, stone column, and upstream asphalt facing alternatives as well as additional project elements.

The downstream stabilization buttress is the preferred and State Division of Safety of Dams (DSOD) approved alternative. It would include construction of an earthen buttress with a drainage system and slope protection. The Project would also involve removal of existing foundation material at the base of the dam; tree and vegetation removal; and hauling and processing of earthen material from existing stockpiles of previously dredged material from Lake Gregory and Lake Arrowhead.

The cement deep soil mixing (CDSM) alternative would consist of injecting CDSM to form columns that would provide stiffness and reduce liquefaction potential. Columns would be placed in a grid pattern across the embankment. The stone column alternative would consist of construction of a series of columns arranged in three rows across the embankment to provide stiffness. The upstream asphalt alternative involves construction of a firm, semi permeable asphalt slope upstream of the dam. Additional soil will come from 3 acres of borrow sites (Ponderosa 1 and 2) and waste material will be stockpiled at the existing Thousand Pines Stockpile site (Figure 2).

Lake Gregory is located in the San Bernardino Mountains approximately 14 miles north of the City of San Bernardino in the community of Crestline. Specifically, the Lake Gregory Dam is mapped on Section 23 of Township 2 North, Range 4 West of the San Bernardino North, USGS 7.5’ quadrangle in the San Bernardino Base and Meridian. The haul road is located on the San Bernardino North and Silverwood Lake USGS 7.5’ quadrangles on Sections 14, 22, and 23 of Township 2 North, Range West.

Lake Gregory Dam Paleontology Memorandum

Figure 2. Project area

Lake Gregory Dam Paleontology Memorandum

PROJECT PERSONNEL

Cogstone Resource Management Inc. (Cogstone) conducted the paleontological resources studies. Sherri Gust, a Qualified Paleontologist, served as the Principal Investigator for the project, supervised all work, wrote the conclusions and recommendations, and edited this report. She has a M.S. in Anatomy (Evolutionary Morphology) from the University of Southern California, a B.S. in Anthropology from the University of California at Davis and over 35 years of experience in California.

Courtney Richards prepared sections of the report. Richards has an M.S. in Biological Sciences with an emphasis in Paleontology from Marshall University. Kim Scott updated this report for the new borrow areas in 2015. Ms. Scott has a M.S. in Biology with an emphasis in Paleontology from California State University, San Bernardino, a B.S. in Geology with an emphasis in Paleontology from University of California, Los Angeles and over 20 years of experience in California geology and paleontology. André Simmons prepared the GIS maps throughout this report. Simmons has a M. A. in Anthropology specializing in Anthropological Archaeology from California State University, Fullerton, a B.A. in Anthropology also from CSUF, cross-training in paleontology, and more than four years of GIS experience with certification. Lindsay Porras performed the cultural and paleontological resources field survey. Ms. Porras holds a B.A. in Anthropology from the University of Nevada, Reno, and has more than six years of experience in California archaeology and paleontology.

Qualifications of key project personnel are available online at www.cogstone.com.

Lake Gregory Dam Paleontology Memorandum

BACKGROUND

GEOLOGICAL SETTING

The Project is located within the Transverse Range Geomorphic Province. The Transverse Ranges are an east-west trending series of mountain ranges and valleys that run oblique to the normal northwest trend of mountain ranges in coastal California. These ranges are the result of the Pacific and North American Plates grinding past each other and “catching” along the bend in the San Andreas Fault Zone. The Transverse Ranges Geomorphic Province is one of the most rapidly rising regions of the earth due to intense north-south compression (Wagner 2002).

STRATIGRAPHY

The surface of the discontinuous Project Area is mapped almost entirely as Mesozoic plutonic rocks (Dibblee 2004, 2008). A small portion of Lake Gregory is mapped as Holocene alluvial sediments (Dibblee 2004).

MESOZOIC PLUTONIC ROCKS

Within the Project, the Jurassic to Cretaceous (199.6 to 65.5 million years old) plutonic rocks consist of quartz monzonite, granodiorite, and tonalite. Rocks around Lake Gregory are medium grained, massive, gray-white to light gray biotite monzogranite granodiorite and massive to gneissoid tonalite. The Lake Arrowhead area is made up of quartz monzonite that is massive, gray to white, and medium to coarse grained (Dibblee 2004; 2008).

HOLOCENE ALLUVIAL SEDIMENTS These young, surficial sediments were deposited in valley areas during the Holocene (<11.7 thousand years ago). Sediments consist of unconsolidated, undissected alluvial gravel and sand derived from rocks of the San Bernardino County Mountains (Dibblee 2004).

Lake Gregory Dam Paleontology Memorandum

Figure 3. Geology of project area

Lake Gregory Dam Paleontology Memorandum

RECORD SEARCHES

Paleontological records searches of Lake Gregory were conducted at the San Bernardino County Museum (SBCM; Scott 2014) and in online databases and literature (UCMP 2014, LACMIP 2014, PBDB 2014, Jefferson 1991). All searches were negative for fossils within the Project or vicinity. Further, it was determined that the geologic units of the Project area have low (Holocene alluvium) to no (Mesozoic plutonic rocks) potential for paleontological resources (Scott 2014).

Scott re-reviewed the previous paleontological records search and reviewed the relevant geological maps and literature for paleontological sensitivity on May 21, 2015 and found that the 2015 updated borrow sites are also in Mesozoic plutonic rocks. These rocks are ranked very low or PFYC 1 as they do not contain fossils due to the way they form.

PALEONTOLOGICAL SENSITIVITY

Paleontological sensitivity was determined using the Potential Fossil Yield Classification (PFYC), which has a multi-level scale based on demonstrated yield of fossils (Appendix B). Occurrences of fossil resources are closely tied to the geologic units (e.g., formations or members) that contain them. The probability for finding significant fossils in a project area can be broadly predicted from previous records of fossils recovered from the geologic units present in and/or adjacent to the study area.

Using the PFYC system, geologic units are classified based on the relative abundance of vertebrate fossils or scientifically significant invertebrate or plant fossils and their sensitivity to adverse impacts. This ranking is not designed to be applied to specific paleontological localities or small areas within units. Although significant localities may occasionally occur in a geologic unit, a few widely scattered important fossils or localities do not necessarily indicate a higher PFYC value; instead, the relative abundance of localities is intended to be the major determinant for the value assignment. Geological setting and fossil localities were considered in determining paleontological sensitivity according to PFYC criteria.

Mesozoic plutonic rocks were ranked very low or PFYC 1 (Table 1) as they do not contain fossils due to the way they form. The Holocene alluvial sediments were ranked low PFYC scales (Table 1). Due to its young age, it is not sensitive for fossil resources.

Lake Gregory Dam Paleontology Memorandum

Table 1. Paleontological sensitivity rankings

5 3a 1 PFYC ranking very 4 moderate; 3b moderate; 2 very high high patchy undemonstrated low low Map symbol Rock Units (Figure 3) Plutonic rocks qd, qm, qr X Holocene alluvial sediments Qa X

CONCLUSIONS AND RECOMMENDATIONS

Neither the record searches nor background research indicate any sediments sensitive for paleontological resources will be impacted by any of the proposed Project alternatives. No further paleontological work is required. If unanticipated fossils are unearthed during construction, work should be halted in the immediate vicinity of the find until it can be evaluated by a qualified paleontologist.

Lake Gregory Dam Paleontology Memorandum

REFERENCES CITED

Dibblee, T. W. Jr. 2004 Geologic Map of the San Bernardino North/ North ½ of San Bernardino South Quadrangles. San Bernardino and Riverside County, California. Dibblee Geology Center Map # DF-127. Scale 1:24,000. 2008 Geologic Map of the Hesperia 15 Minute Quadrangle. San Bernardino County, California. Dibblee Geology Center Map # DF-382. Scale 1:62,500.

Jefferson, G. T. 1991 A Catalogue of late Quaternary Vertebrates from California: Part two, Mammals. Natural History Museum of Los Angeles, Technical Report #7.

LACMIP 2014 Online database search with Natural History Museum of Los Angeles County Department of Invertebrate Paleontology.

PBDB 2014 Paleobiology Database online records search.

Scott, E. 2014 Paleontology Literature and Records Review, Lake Gregory Dam Project, San Bernardino County, California. On file with Cogstone, Orange, CA.

UCMP 2014 University of California Museum of Paleontology online records search

Wagner, D. L. 2002 California geomorphic provinces. California Geological Survey note 36. Website: http://www.consrv.ca.gov/cgs/information/

Lake Gregory Dam Paleontology Memorandum

APPENDIX A. PALEONTOLOGICAL RECORDS SEARCH

Lake Gregory Dam Paleontology Memorandum

APPENDIX B. PFYC CRITERIA

Lake Gregory Dam Paleontology Memorandum

POTENTIAL FOSSIL YIELD CLASSIFICATION SYSTEM

The Potential Fossil Yield Classification System (PFYC) System was developed by the United States Department of Agriculture (USDA) Forest Service and refined by the BLM (2007). It is utilized here as a best professional practice. Occurrences of paleontological resources are closely tied to the geologic units (i.e., formations, members, or beds) that contain them. The probability for finding paleontological resources can be broadly predicted from the geologic units present at or near the surface. Therefore, geologic mapping can be used for assessing the potential for the occurrence of paleontological resources.

Using the PFYC system, geologic units are classified based on the relative abundance of vertebrate fossils or scientifically significant invertebrate or plant fossils and their sensitivity to adverse impacts, with a higher class number indicating a higher potential. This classification is applied to the geologic formation, member, or other distinguishable unit, preferably at the most detailed mapable level. It is not intended to be applied to specific paleontological localities or small areas within units. Although significant localities may occasionally occur in a geologic unit, a few widely scattered important fossils or localities do not necessarily indicate a higher class; instead, the relative abundance of significant localities is intended to be the major determinant for the class assignment.

The PFYC system is meant to provide baseline guidance for predicting, assessing, and mitigating paleontological resources. The classification should be considered at an intermediate point in the analysis, and should be used to assist in determining the need for further mitigation assessment or actions.

The descriptions for the classes below are written to serve as guidelines rather than as strict definitions. Knowledge of the geology and the paleontological potential for individual units or preservational conditions should be considered when determining the appropriate class assignment. Assignments are best made by collaboration between land managers and knowledgeable researchers.

CLASS 1 – VERY LOW. Geologic units that are not likely to contain recognizable fossil remains. The probability for impacting any fossils is negligible. Assessment or mitigation of paleontological resources is usually unnecessary. The occurrence of significant fossils is non-existent or extremely rare. This class includes: • Units that are igneous or metamorphic, excluding reworked volcanic ash units. • Units that are Precambrian in age or older.

Class 1 Management notes: (1) Management concern for paleontological resources is generally low. (2) Assessment or mitigation is usually unnecessary except in rare or isolated circumstances.

CLASS 2 – LOW. Sedimentary geologic units that are not likely to contain vertebrate fossils or scientifically significant nonvertebrate fossils. The probability for impacting vertebrate fossils or scientifically significant invertebrate or plant fossils is low. Assessment or mitigation of paleontological resources is not likely to be necessary. Localities containing important resources may exist, but would be

Lake Gregory Dam Paleontology Memorandum

rare and would not influence the classification. These important localities would be managed on a case- by-case basis. This class includes: • Vertebrate or significant invertebrate or plant fossils not present or very rare. • Units that are generally younger than 10,000 years before present. • Recent aeolian deposits. • Sediments that exhibit significant physical and chemical changes (i.e., diagenetic alteration).

Class 2 Management notes: (1) Management concern for paleontological resources is generally low. (2) Assessment or mitigation is usually unnecessary except in rare or isolated circumstances.

CLASS 3 – MODERATE OR UNKNOWN. Fossiliferous sedimentary geologic units where fossil content varies in significance, abundance, and predictable occurrence; or sedimentary units of unknown fossil potential. This classification includes a broad range of paleontological potential. It includes geologic units of unknown potential, as well as units of moderate or infrequent occurrence of significant fossils. Management considerations cover a broad range of options as well, and could include pre- disturbance surveys, monitoring, or avoidance. Surface-disturbing activities will require sufficient assessment to determine whether significant paleontological resources occur in the area of a proposed action, and whether the action could affect the paleontological resources. These units may contain areas that would be appropriate to designate as hobby collection areas due to the higher occurrence of common fossils and a lower concern about affecting significant paleontological resources. This class includes: • Formations with sporadic known occurrences of vertebrate fossils - often marine in origin. • Vertebrate fossils and scientifically significant invertebrate or plant fossils known to occur intermittently; predictability known to be low. • Poorly studied and/or poorly documented formations. Potential yield cannot be assigned without ground reconnaissance.

Class 3 Management notes: (1) Management concern for paleontological resources is moderate; or cannot be determined from existing data. (2) Surface-disturbing activities may require field assessment to determine appropriate course of action.

CLASS 3A – MODERATE POTENTIAL. Units are known to contain vertebrate fossils or scientifically significant nonvertebrate fossils, but these occurrences are widely scattered. Common invertebrate or plant fossils may be found in the area, and opportunities may exist for hobby collecting. The potential for a project to be sited on or impact a significant fossil locality is low, but is somewhat higher for common fossils.

CLASS 3B – UNKNOWN POTENTIAL. Units exhibit geologic features and preservational conditions that suggest significant fossils could be present, but little information about the paleontological resources of the unit or the area is known. This may indicate the unit or area is poorly studied, and field surveys may uncover significant finds. The units in this Class may eventually be placed in another Class when

Lake Gregory Dam Paleontology Memorandum

sufficient survey and research is performed. The unknown potential of the units in this Class should be carefully considered when developing any mitigation or management actions.

CLASS 4 – HIGH. Geologic units containing a high occurrence of significant fossils. Vertebrate fossils or scientifically significant invertebrate or plant fossils are known to occur and have been documented, but may vary in occurrence and predictability. Surface disturbing activities may adversely affect paleontological resources in many cases. The probability for impacting significant paleontological resources is moderate to high, and is dependent on the proposed action. Mitigation considerations must include assessment of the disturbance, such as removal or penetration of protective surface alluvium or soils, potential for future accelerated erosion, or increased ease of access resulting in greater looting potential. If impacts to significant fossils can be anticipated, on-the-ground surveys prior to authorizing the surface disturbing action will usually be necessary. On-site monitoring or spot-checking may be necessary during construction activities. This class includes: • Extensive soil or vegetative cover; bedrock exposures are limited or not expected to be impacted. • Areas of exposed outcrop are smaller than two contiguous acres. • Outcrops from cliffs of sufficient height and slope so that impacts are minimized by topographic conditions. • Other characteristics are present that lower the vulnerability of both known and unidentified paleontological resources.

Class 4 Management notes: (1) Management concern for paleontological resources in Class 4 is moderate to high, depending on the proposed action. (2) A field survey by a qualified paleontologist is often needed to assess local conditions. (3) Management prescriptions for resource preservation and conservation through controlled access or special management designation should be considered. (4) Class 4 and Class 5 units may be combined as Class 5 for broad applications, such as planning efforts or preliminary assessments, when geologic mapping at an appropriate scale is not available. Resource assessment, mitigation, and other management considerations are similar at this level of analysis, and impacts and alternatives can be addressed at a level appropriate to the application.

CLASS 4A – HIGH AND EXPOSED. Unit is exposed with little or no soil or vegetative cover. Outcrop areas are extensive with exposed bedrock areas often larger than two acres. Paleontological resources may be susceptible to adverse impacts from surface disturbing actions. Illegal collecting activities may impact some areas.

CLASS 4B – HIGH AND UNEXPOSED. These are areas underlain by geologic units with high potential but have lowered risks of human-caused adverse impacts and/or lowered risk of natural degradation due to moderating circumstances. The bedrock unit has high potential, but a protective layer of soil, thin alluvial material, or other conditions may lessen or prevent potential impacts to the bedrock resulting from the activity.

Lake Gregory Dam Paleontology Memorandum

CLASS 5 – VERY HIGH. Highly fossiliferous geologic units that consistently and predictably produce vertebrate fossils or scientifically significant invertebrate or plant fossils, and that are at risk of human-caused adverse impacts or natural degradation. The probability for impacting significant fossils is high. Vertebrate fossils or scientifically significant invertebrate fossils are known or can reasonably be expected to occur in the impacted area. On-the-ground surveys prior to authorizing any surface disturbing activities will usually be necessary. On-site monitoring may be necessary during construction activities. This class includes: • Extensive soil or vegetative cover; bedrock exposures are limited or not expected to be impacted. • Areas of exposed outcrop are smaller than two contiguous acres. • Outcrops from cliffs of sufficient height and slope so that impacts are minimized by topographic conditions. • Other characteristics are present that lower the vulnerability of both known and unidentified paleontological resources.

Class 5 Management notes: (1) Management concern for paleontological resources in Class 5 areas is high to very high. (2) A field survey by a qualified paleontologist is usually necessary prior to surface disturbing activities or land tenure adjustments. Mitigation will often be necessary before and/or during these actions. (3) Official designation of areas of avoidance, special interest, and concern may be appropriate.

CLASS 5A – VERY HIGH AND EXPOSED. Unit is exposed with little or no soil or vegetative cover. Outcrop areas are extensive with exposed bedrock areas often larger than two contiguous acres. Paleontological resources are highly susceptible to adverse impacts from surface disturbing actions. Unit is frequently the focus of illegal collecting activities.

CLASS 5B – VERY HIGH AND UNEXPOSED. These are areas underlain by geologic units with very high potential but have lowered risks of human-caused adverse impacts and/or lowered risk of natural degradation due to moderating circumstances. The bedrock unit has very high potential, but a protective layer of soil, thin alluvial material, or other conditions may lessen or prevent potential impacts to the bedrock resulting from the activity. [BLM 2007]