Client: City of Pomona Project: Pedley Spreading Grounds Pond Enhancements
Site Location: Claremont, CA
Photograph ID: 1
Photo Location:
34.117027°, -117.710329°
Direction:
East
Survey Date:
5/2/2022
Comments:
Common deerweed
shrubland.
Photograph ID: 2
Photo Location:
34.115774°, -117.709707°
Direction:
Northeast
Survey Date:
5/2/2022
Comments:
Mulefat thickets.
Photographic Log
Client: City of Pomona Project: Pedley Spreading Grounds Pond Enhancements
Site Location: Claremont, CA
Photograph ID: 3
Photo Location:
34.116698°, -117.710125°
Direction:
South
Survey Date:
5/2/2022
Comments:
Retention pond.
Photograph ID: 4
Photo Location:
34.116867°, -117.710506°
Direction:
Northwest
Survey Date:
5/2/2022
Comments:
Culvert draining to
retention pond.
Photographic Log
Client: City of Pomona Project: Pedley Spreading Grounds Pond Enhancements
Site Location: Claremont, CA
Photograph ID: 5
Photo Location:
34.116867°, -117.710506°
Direction:
Northwest
Survey Date:
5/2/2022
Comments:
Vegetated channel.
Photograph ID: 6
Photo Location:
34.116813°, -117.710763°
Direction:
Southwest
Survey Date:
5/2/2022
Comments:
Additional culvert draining
to retention pond.
Photographic Log
Client: City of Pomona Project: Pedley Spreading Grounds Pond Enhancements
Site Location: Claremont, CA
Photograph ID: 7
Photo Location:
34.117182°, -117.710790°
Direction:
Southwest
Survey Date:
5/2/2022
Comments:
dried retention pond.
Photograph ID: 8
Photo Location:
34.117200°, -117.711311°
Direction:
Northwest
Survey Date:
5/2/2022
Comments:
Vegetated channel leading
to dried retention pond.
Photographic Log
Client: City of Pomona Project: Pedley Spreading Grounds Pond Enhancements
Site Location: Claremont, CA
Photograph ID: 9
Photo Location:
34.117235°, -117.711445°
Direction:
West
Survey Date:
5/2/2022
Comments:
Culvert for dried retention
pond.
Photograph ID: 10
Photo Location:
34.117249°, -117.710688°
Direction:
Northeast
Survey Date:
5/2/2022
Comments:
Ruderal herbacious land
cover.
Photographic Log
Client: City of Pomona Project: Pedley Spreading Grounds Pond Enhancements
Site Location: Claremont, CA
Photograph ID: 11
Photo Location:
34.117297°, -117.711219°
Direction:
Northeast
Survey Date:
5/2/2022
Comments:
Common deerweed
shrubland with mulefat
thickets along pond edge.
Photograph ID: 12
Photo Location:
34.116502°, -117.710678°
Direction:
East
Survey Date:
5/2/2022
Comments:
Variation in vegetation on
site.
Photographic Log
Client: City of Pomona Project: Pedley Spreading Grounds Pond Enhancements
Site Location: Claremont, CA
Photograph ID: 13
Photo Location:
34.115290°, -117.711294°
Direction:
North
Survey Date:
5/2/2022
Comments:
Variation in vegetation on
site.
Photograph ID: 14
Photo Location:
34.117169°, -117.709513°
Direction:
North
Survey Date:
5/2/2022
Comments:
Variation in vegetation on
site.
Photographic Log
Client: City of Pomona Project: Pedley Spreading Grounds Pond Enhancements
Site Location: Claremont, CA
Photograph ID: 15
Photo Location:
34.117368°, -117.709894°
Direction:
East
Survey Date:
5/2/2022
Comments:
Common deerweed
shrubland.
Photograph ID: 16
Photo Location:
34.120593°, -117.707362°
Direction:
North
Survey Date:
5/2/2022
Comments:
Residential landscape.
CEQA Initial Study
Appendix C
Paleontological Resource Assessment
Pedley Spreading Grounds Pond Enhancements
Stantec Project Number 184031542
Draft Paleontological Resource
Assessment for the Pedley
Spreading Grounds – Pond
Enhancements Project, Los
Angeles County, California
Results of an Analysis of Existing Data
and Impacts Assessment
February 6, 2023
Prepared for:
The City of Pomona
Prepared by:
Alyssa Bell, Ph.D.
Principal Paleontologist
and
Ben Kerridge, M.A.
Paleontologist
Stantec Consulting Services Inc.
300 North Lake Avenue, Suite 400
Pasadena, California 91101
ii
DRAFT PALEONTOLOGICAL RESOURCE ASSESSMENT FOR THE PEDLEY SPREADING GROUNDS –
POND ENHANCEMENTS PROJECT, LOS ANGELES COUNTY, CALIFORNIA
iii
Revision Description Autho r Qualit y Check Independent Review
DRAFT PALEONTOLOGICAL RESOURCE ASSESSMENT FOR THE PEDLEY SPREADING GROUNDS –
POND ENHANCEMENTS PROJECT, LOS ANGELES COUNTY, CALIFORNIA
iv
The conclusions in the Report are Stantec’s professional opinion, as of the time of the Report, and concerning the scope described in the Report. The opinions in the document are based on conditions and information existing at the time the document was published and do not take into account any subsequent changes. The Report relates solely to the specific project for which Stantec was retained and the stated purpose for which the Report was prepared. The Report is not to be used or relied on for any variation or extension of the project, or for any other project or purpose, and any unauthorized use or reliance is at the recipient’s own risk.
Stantec has assumed all information received from the Client and third parties in the preparation of the Report to be correct. While Stantec has exercised a customary level of judgment or due diligence in the use of such information, Stantec assumes no responsibility for the consequences of any error or omission contained therein.
This Report is intended solely for use by the Client in accordance with Stantec’s contract with the Client.
While the Report may be provided to applicable authorities having jurisdiction and others for whom the Client is responsible, Stantec does not warrant the services to any third party. The report may not be relied upon by any other party without the express written consent of Stantec, which may be withheld at Stantec’s discretion.
Prepared by
(signature)
Alyssa Bell, Ph.D.; Principal Paleontologist
Reviewed by
(signature)
Geraldine Aron, M.S.; Business Center Practice Lead
Approved by
(signature)
Sarah Garber, M.S.; Senior Principal
DRAFT PALEONTOLOGICAL RESOURCE ASSESSMENT FOR THE PEDLEY SPREADING GROUNDS – POND ENHANCEMENTS PROJECT, LOS ANGELES COUNTY, CALIFORNIA
v
Table of Contents
EXECUTIVE SUMMARY ........................................................................................................... VII ABBREVIATIONS ...................................................................................................................... IX GLOSSARY ................................................................................................................................. X
1.0 INTRODUCTION .............................................................................................................. . 1
1.1 PROJECT DESCRIPTION ................................................................................................ 1
1.2 PROJECT LOCATION ...................................................................................................... 1
1.3 PALEONTOLOGICAL RESOURCES ............................................................................... 1
2.0 REGULATORY FRAMEWORK ........................................................................................ 5
2.1 STATE OF CALIFORNIA .................................................................................................. 5
2.1.1 California Environmental Quality Act ............................................................... 5
2.1.2 Public Resources Code ................................................................................... 6
2.2 LOCAL REGULATIONS ....................................... ERROR! BOOKMARK NOT DEFINED.
2.2.1 City of Pomona General Plan .......................... Error! Bookmark not defined.
3.0 PROFESSIONAL STANDARDS ...................................................................................... 6
4.0 GEOLOGIC SETTING ...................................................................................................... 6
5.0 METHODOLOGY .............................................................................................................. 7
5.1 ANALYSIS OF EXISTING DATA ...................................................................................... 7
5.2 PALEONTOLOGICAL RESO URCES ASSESSMENT ...................................................... 8
5.3 PALEONTOLOGICAL RESOURC ES IMPACTS ASSESSMENT ..................................... 8
6.0 RESULTS ................................................................................................................... ...... 9
6.1 PROJECT AREA GEOLOGY ............................................................................................ 9
6.2 PROJECT AREA PALEONTOLOGY .............................................................................. 12
6.3 PALEONTOLOGICAL RESOURC ES IMPACTS ASSESSMENT ................................... 13
7.0 RECOMMENDATIONS AND MANAGEMENT CONSIDERATIONS ............................. 14
8.0 REFERENCES ................................................................................................................ 15
LIST OF TABLES
Table 1 Summary of the records search from the LACM ............................................................ 13 Table 2 Paleontological potential of geologic units within the Project area................................. 13
LIST OF FIGURES
Figure 1. Project vicinity ................................................................................................................ 2 Figure 2. Project area ................................................................................................................... 3
DRAFT PALEONTOLOGICAL RESOURCE ASSESSMENT FOR THE PEDLEY SPREADING GROUNDS – POND ENHANCEMENTS PROJECT, LOS ANGELES COUNTY, CALIFORNIA
vi
Figure 3. Geologic map of the Project area ................................................................................ 11
LIST OF APPENDICES
................................................. 1
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vii
Executive Summary
Stantec Consulting Services Inc. (Stantec) conducted a paleontological resources assessment on behalf of the City of Pomona for the Pedley Spreading Grounds – Pond Enhancement Project (the Project) located at 1691 Longwood Avenue, within the City of Claremont, Los Angeles County, California. This paleontological study was conducted in support of the City of Pomona for the proposed reoperation of the 30-inch storm drain on Mills Avenue, regrading of the existing basins, and improvements to Chaparral Park.
The proposed Project is subject to compliance with the California Environmental Quality Act (CEQA) requirements regarding the Project's potential impacts on paleontological resources. As part of CEQA compliance, a paleontological resources assessment was conducted to assess potential impacts of the proposed Project on paleontological resources.
This paleontological resource investigation consisted of a museum records search from the Natural History Museum of Los Angeles County of the Project area and vicinity, as well as a review of the most recent geologic mapping, relevant scientific literature and reporting, and a search of online collections databases. This research was used to assign paleontological potential rankings of the Society of Vertebrate Paleontology (2010) to the geologic units present in the Project area, either at the surface or in the subsurface. The results of this assessment indicate that young alluvial fan deposits are mapped in the Project area, which have low-to-high paleontological potential, increasing with depth. These sediments are likely underlain by very old alluvial fan deposits in the subsurface, which are assessed as having high paleontological potential. Project plans for ground disturbance involve regrading of the existing pond basins and potholing to expose the existing utilities. Of these, the regrading of the existing basins may occur in geologic units with high paleontological potential and therefore may encounter paleontological resources. In order to avoid impacts to paleontological resources, Stantec recommends the following mitigation activities for the Project:
1. A paleontologist meeting profes sional standards as defined by Murphey et al. (2019) shall be retained as the Project Paleontologist to oversee all aspects of paleontological mitigation, including the development and implementation of a Paleontological Monitoring and Mitigation Plan (PMMP) tailored to the Project plans that provides for paleontological monitoring of earthwork and ground disturbing activities into undisturbed geologic units with high paleontological potential to be conducted by a paleontological monitor meeting industry standards (Murphey et al. 2019). A final monitoring report summarizing the results of the monitoring program should be prepared at the conclusion of Project ground disturbance.
2. The PMMP should include provisions for a Wo rkers’ Environmental Awareness Program training that communicates requirements and procedures for the inadvertent discovery of paleontological resources during construction, to be delivered by the paleontological monitor to the construction crew prior to the onset of ground disturbance.
DRAFT PALEONTOLOGICAL RESOURCE ASSESSMENT FOR THE PEDLEY SPREADING GROUNDS – POND ENHANCEMENTS PROJECT, LOS ANGELES COUNTY, CALIFORNIA
viii
3. The PMMP should provide for full time paleontological monitoring of grading in the existing basins at any depth, and of other ground disturbing activities that exceed 5 feet in depth below the natural ground surface in previously undisturbed sediments. The Project Paleontologist may reduce the frequency of monitoring or spot checks should subsurface conditions indicate low paleontological potential.
4. Should a potential paleontological resource be id entified in the Project area, whether by the monitor or a member of the construction crew, work should halt in a safe radius around the find (usually 50 feet) until the Project Paleontologist can assess the find and, if significant, salvage the fossil for laboratory preparation and curation at the Natural History Museum of Los Angeles County.
Based on the findings in this study and the implementation of the above mitigation activities, the proposed Project should not cause an adverse impact to paleontological resources. Therefore, no additional paleontological resource studies are recommended or required at this time. Changes to the Project location or plans from those assessed in this study will require additional assessment for impacts to paleontological resources.
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ix
Abbreviations
Bgs below ground surface
CEQA California Environmental Quality Act
GIS Geographic Information System
LACM Natural History Museum of Los Angeles County
Ma Million years ago
PSG Pedley Spreading Grounds
Stantec Stantec Consulting Services Inc.
SVP Society of Vertebrate Paleontology
UCMP University of California Museum of Paleontology
DRAFT PALEONTOLOGICAL RESOURCE ASSESSMENT FOR THE PEDLEY SPREADING GROUNDS – POND ENHANCEMENTS PROJECT, LOS ANGELES COUNTY, CALIFORNIA
x
Glossary
Paleontological Monitor A person meeting or ex ceeding the following qualifications: B.S. or B.A. degree in geology or paleontology and one year of experience monitoring in the state or geologic province of the specific project. An associate degree and/or demonstrated experience showing ability to recognize fossils in a biostratigraphic context and recover vertebrate fossils in the field may be substituted for a degree.
Paleontological Monitoring Full-time observati on of construction activities in high potential geologic units by a paleontological monitor, under supervision of the project paleontologist.
Paleontological Resource Any fossilized remains, tr aces, or imprints of organisms, preserved in or on the earth’s crust, that are of paleontological interest and that provide information about the history of life on earth, except that the term does not include— (A) any materials associated with an archaeological resource (as defined in section 3(1) of the Archaeological Resources Protection Act of 1979 (16 U.S.C. 470bb(1)); or (B) any cultural item (as defined in section 2 of the Native American Graves Protection and Repatriation Act (25 U.S.C. 3001)). [Paleontological Resources Preservation Act; Sec. 6301:
Definitions]
Project Paleontologist An individual who is recognized in the paleontological community as a professional and can demonstrate familiarity and proficiency with paleontology in a stratigraphic context, including fossil identification and recovery, with the equivalent of the following qualifications: a graduate degree in paleontology or geology, and/or a publication record in peer reviewed journals; demonstrated competence in field techniques, preparation, identification, curation, and reporting in the state or geologic province in which the project occurs; at least two full years professional experience as assistant to a Project Paleontologist with administration and project management experience; experience collecting vertebrate fossils in the field. [Society of Vertebrate Paleontology 2010]
DRAFT PALEONTOLOGICAL RESOURCE ASSESSMENT FOR THE PEDLEY SPREADING GROUNDS – POND ENHANCEMENTS PROJECT, LOS ANGELES COUNTY, CALIFORNIA
xi
Spot check A short inspection of exca vations and subsurface conditions conducted by the paleontological monitor in order to confirm excavations are impacting low potential geologic units.
DRAFT PALEONTOLOGICAL RESOURCE ASSESSMENT FOR THE PEDLEY SPREADING GROUNDS – POND ENHANCEMENTS PROJECT, LOS ANGELES COUNTY, CALIFORNIA Introduction
Project Number: 184031542 1
1.0 INTRODUCTION
Stantec Consulting Services Inc. (Stantec) conducted a paleontological resources assessment on behalf of the City of Pomona for the Pedley Spreading Grounds (PSG) – Pond Enhancements Project (the Project) located at 1691 Longwood Avenue within the City of Claremont, Los Angeles County, California.
This paleontological study was conducted in support of the City of Pomona for the proposed pond enhancement project.
The proposed Project is subject to compliance with the California Environmental Quality Act (CEQA) requirements regarding the Project's potential impacts on paleontological resources. As part of CEQA compliance, a paleontological resources assessment was conducted to assess potential impacts of the proposed Project on paleontological resources.
1.1 PROJECT DESCRIPTION
The City of Pomona proposes to capture, treat, and infiltrate local urban runoff into the existing PSG to increase water supply through stormwater recharge and to decrease impact of non-point source pollutants for receiving waters. The Project will reoperate the 30-inch storm drain on Mills Avenue by removing the weir at the existing junction structure at Baseline Road and Mills Avenue. The existing basins will be regraded to increase their capacity, and additional grading will occur to enhance access for maintenance. An additional feature of the Project will be updates to Chaparral Park, north of the PSG, through new park and educational features.
1.2 PROJECT LOCATION
The proposed Project is located at 1691 Longwood Avenue, within the City of Claremont, Los Angeles County (Figure 1). Specifically, the Project site is bound by an access road that encircles the PSG property. Residential development abuts the Project site on the northwest, north, south, and southeast, with the Claremont Colleges Campus immediately adjacent to the southwest, and Chaparral Elementary School and Chaparral Park to the northeast. The Project site is located on Los Angeles County Assessor Parcel Number 8306-007-270. Specifically, the Project area is located in the southeast quarter of the northwest quarter of Section 3, Township 1 South, Range 8 West, as depicted on the Ontario, California United States Geological Survey 7.5-minute series topographic quadrangle (Figure 2).
1.3 PALEONTOLOGICAL RESOURCES
Fossils are any evidence of ancient life. This includes the remains of the body of an organism, such as bones, skin impressions, shell, or leaves, as well as traces of an organism’s activity, such as footprints or burrows, called trace fossils. In addition to the fossils themselves, geologic context is an important
DRAFT PALEONTOLOGICAL RESOURCE ASSESSMENT FOR THE PEDLEY SPREADING GROUNDS – POND ENHANCEMENTS PROJECT, LOS ANGELES COUNTY, CALIFORNIA Introduction
Project Number: 184031542 2
Figure 1. Project vicinity
DRAFT PALEONTOLOGICAL RESOURCE ASSESSMENT FOR THE PEDLEY SPREADING GROUNDS – POND ENHANCEMENTS PROJECT, LOS ANGELES COUNTY, CALIFORNIA Introduction
Project Number: 184031542 3
Figure 2. Project area
DRAFT PALEONTOLOGICAL RESOURCE ASSESSMENT FOR THE PEDLEY SPREADING GROUNDS – POND ENHANCEMENTS PROJECT, LOS ANGELES COUNTY, CALIFORNIA Introduction
Project Number: 184031542 4
component of paleontological resources and includes the stratigraphic placement of the fossil as well as the lithology of the rock in order to assess paleoecologic setting, depositional environment, and taphonomy. Fossils are protected by federal, state, and local regulations as nonrenewable natural resources.
While CEQA does not define a significance threshold for paleontological resources, the standards of the Society of Vertebrate Paleontology (SVP) are often used in the absence of a legal definition of significance. The SVP defines significant paleontological resources as:
identifiable vertebrate fossils, large or small, uncommon invertebrate, plant, and trace fossils, and other data that provide taphonomic, taxonomic, phylogenetic, paleoecologic, stratigraphic, and/or biochronologic information. Paleontological resources are considered to be older than recorded human history and/or older than middle Holocene (i. e., older than about 5,000 radiocarbon years). [SVP 2010: 11].
It should be noted that the threshold for significance varies factors including geologic unit, geographic area, and the current state of scientific research, and may also vary between different agencies (Murphey et al. 2019). Numerous paleontological studies have developed criteria for the assessment of significance for fossil discoveries (e.g., Eisentraut and Cooper 2002, Murphey et al. 2019, Murphey and Daitch 2007, Scott and Springer 2003). In general, these studies assess fossils as significant if one or more of the following criteria apply:
• The fossils provide information on the evolutionary relationships and developmental trends among organisms, living or extinct.
• The fossils provide data useful in determining the age(s) of the rock unit or sedimentary stratum, including data important in determining the depositional history of the region and the timing of geologic events, through biochronology or biostratigraphy and the correlation with isotopic dating.
• The fossils provide ecological data, such as the development of biological communities, the interaction between paleobotanical and paleozoological biotas, or the biogeography of lineages. • The fossils demonstrate unusual or spectacular circumstances in the history of life. • The fossils provide information on the preser vational pathways of paleontological resources, including taphonomy, diagenesis, or preservational biases in the fossil record. • The fossils are in short supply and/or in dang er of being depleted or destroyed by the elements, vandalism, or commercial exploitation, and are not found in other geographic locations. • The fossils inform our understanding of anthropoge nic affects to global environments or climate.
A geologic unit known to contain paleontological resources is considered sensitive to adverse impacts if there is a high probability that earth-moving or ground-disturbing activities in that rock unit will either
DRAFT PALEONTOLOGICAL RESOURCE ASSESSMENT FOR THE PEDLEY SPREADING GROUNDS – POND ENHANCEMENTS PROJECT, LOS ANGELES COUNTY, CALIFORNIA Regulatory Framework
Project Number: 184031542 5
disturb or destroy fossil remains directly or indirectly. This definition of sensitivity differs fundamentally from the definition for archaeological resources as follows:
It is extremely important to distinguish between archaeological and paleontological (fossil) resource sites when defining the sensitivity of rock units. The boundaries of archaeological sites define the areal extent of the resource. Paleontological sites, however, indicate that the containing sedimentary rock unit or formation is fossiliferous. The limits of the entire rock formation, both areal and stratigraphic, therefore define the scope of the paleontological potential in each case. [SVP 2010: 2].
Many archaeological sites contain features that are visually detectable on the surface. In contrast, fossils are often contained within surficial sediments or bedrock and are therefore not observable or detectable unless exposed by erosion or human activity.
In summary, in the absence of observable fossil resources on the surface, paleontologists must assess the potential of geologic units as a whole to yield paleontological resources based on their known potential to produce significant fossils elsewhere. Monitoring by experienced paleontologists greatly increases the probability that fossils will be discovered during ground-disturbing activities and that, if these remains are significant, successful mitigation and salvage efforts may be undertaken to prevent adverse impacts to these resources.
2.0 REGULATORY FRAMEWORK
California and the City of Pomona have enacted multiple laws and regulations that provide for the protection of paleontological resources. This investigation was conducted to meet these requirements regarding paleontological resources on the lands proposed for development.
2.1 STATE OF CALIFORNIA
2.1.1 California Environmental Quality Act
CEQA (Public Resources Code Sections 21000 et seq) requires that before approving most discretionary projects, the Lead Agency must identify and examine any significant adverse environmental effects that may result from activities associated with such projects. As updated in 2016, CEQA separates the consideration of paleontological resources from cultural resources (Public Resources Code Section 21083.09). The Appendix G checklist (Title 14, Division 6, Chapter 3, California Code of Regulations 15000 et seq.) requires an answer to the question, “Will the proposed project directly or indirectly destroy a unique paleontological resource or site or unique geologic feature?” Under these requirements, Stantec has conducted a paleontological resources assessment to determine impacts of the proposed project on paleontological resources within the Project area.
DRAFT PALEONTOLOGICAL RESOURCE ASSESSMENT FOR THE PEDLEY SPREADING GROUNDS – POND ENHANCEMENTS PROJECT, LOS ANGELES COUNTY, CALIFORNIA Professional Standards
Project Number: 184031542 6
2.1.2 Public Resources Code
The California Public Resources Code (Chapter 1.7, Sections 5097 and 30244) includes additional state- level requirements for the assessment and management of paleontological resources. These statutes require reasonable mitigation of adverse impacts to paleontological resources resulting from development on state lands, define the removal of paleontological sites or features from state lands as a misdemeanor, and prohibit the removal of any paleontological site or feature from state land without permission of the applicable jurisdictional agency.
3.0 PROFESSIONAL STANDARDS
The SVP (2010), the Bureau of Land Management (2016) and a number of scientific studies (Eisentraut and Cooper 2002; Murphey et al. 2019; Scott and Springer 2003) have developed guidelines for professional qualifications, conducting paleontological assessments, and developing mitigation measures for the protection of paleontological resources. These guidelines are broadly similar, and include the use of museum records searches, scientific literature reviews, and, in some cases, field surveys to assess the potential of an area to preserve paleontological resources. Should that potential be high, accepted mitigation measures include paleontological monitoring, data recordation of all fossils encountered, collection and curation of significant fossils and associated data, and in some cases screening of sediment for microfossils.
This study has been conducted in accordance with these guidelines and the recommendations provided herein meet these standards.
4.0 GEOLOGIC SETTING
The Project area is located at the northern end of the Peninsular Ranges geomorphic province. The Peninsular Ranges formed as a volcanic island arc collided with the west coast of North America and was accreted onto the margin of the continent, resulting in the expansion of the continent westward. The Peninsular Ranges are part of a larger subduction zone that extends all along western North America, with this particular geomorphic province extending from the Los Angeles Basin in the north to Baja in the south, and extending to Santa Catalina, Santa Barbara, San Nicolas, and San Clemente Islands on the west and the Colorado Desert on the east (Norris and Webb 1990). The core of the Peninsular Ranges formed as the core of a magmatic arc in the Mesozoic that resulted from active subduction along the Pacific Plate boundary (Harden 2004).
Locally, the Project area is in the Los Angeles Basin, a structural depression approximately 50 miles long and 20 miles wide in the northernmost Peninsular Ranges Geomorphic Province (Ingersoll and Rumelhart 1999). The Los Angeles Basin developed as a result of tectonic forces and the San Andreas fault zone, with subsidence occurring 18 – 3 million years ago (Ma) (Critelli et al. 1995). While sediments dating back to the Cretaceous (66 Ma) are preserved in the basin, continuous sedimentation began in the middle
DRAFT PALEONTOLOGICAL RESOURCE ASSESSMENT FOR THE PEDLEY SPREADING GROUNDS – POND ENHANCEMENTS PROJECT, LOS ANGELES COUNTY, CALIFORNIA Methodology
Project Number: 184031542 7
Miocene (around 13 Ma) and continues today, resulting in thousands of feet of accumulation (Yerkes et al. 1965). Most of these sediments are marine, until sea level dropped in the Pleistocene and deposition of the alluvial sediments that compose the uppermost units in the Los Angeles Basin began.
5.0 METHODOLOGY
The paleontological resource assessment reported herein consisted of a records search from the Natural History Museum of Los Angeles County (LACM) as well as a review of the relevant scientific literature, relevant environmental reporting, the most recent geologic mapping, and a review of the online database of the University of California Museum of Paleontology (UCMP). To assess if paleontological resources are likely to be encountered in any given area, the paleontological potential of the geologic units present in the area is assessed. Paleontological potential of a geologic unit consists of both (a) the potential for yielding abundant vertebrate fossils or for yielding significant fossils, large or small, vertebrate, invertebrate, plant, or trace fossils and (b) the importance of recovered evidence for new and significant taxonomic, phylogenetic, paleoecologic, taphonomic, biochronologic, or stratigraphic data (SVP 2010).
Unlike archaeological resources that often have a limited aerial extent, paleontological resources may occur throughout a geologic unit, and so paleontological potential is assessed for the unit as a whole.
Provided below is the methodology used during the current study to assess the potential of the Project to impact paleontological resources.
The paleontological assessment presented here was conducted by Stantec Principal Paleontologist Alyssa Bell, Ph.D. with the assistance of Paleontologist Ben Kerridge, M.A. Geographic Information System (GIS) maps and figures were drafted by GIS analyst Chisa Whelan, M.S. This report was authored by Dr. Bell and Mr. Kerridge and peer reviewed by Business Center Practice Lead Geraldine Aron, M.S. Stantec’s work on this Project was managed by Senior Principal Sarah Garber, M.S., who coordinated all work and provided quality assurance and control.
5.1 ANALYSIS OF EXISTING DATA
In order to assess the paleontological potential of the Project area, Stantec conducted an analysis of existing data. A records search of the Project area and vicinity was requested from the LACM on October 28, 2022, with the results received from the LACM on October 30, 2022. The search returned the closest known paleontological localities of the LACM to the Project area from geologic units that are present at the Project area, either at the surface or in the subsurface.
The most recent geologic mapping was consulted to identify all geologic units present at the surface or likely present in the subsurface. The scientific literature was then consulted to determine the history of each of these units for preserving fossils. The online database of the UCMP was searched for any fossil localities from geologic units relevant to the Project in Los Angeles County or adjoining counties on November 10, 2022. The database of the UCMP does not include precise locality information, but often the general vicinity of the locality can be determined from the available data.
DRAFT PALEONTOLOGICAL RESOURCE ASSESSMENT FOR THE PEDLEY SPREADING GROUNDS – POND ENHANCEMENTS PROJECT, LOS ANGELES COUNTY, CALIFORNIA Methodology
Project Number: 184031542 8
5.2 PALEONTOLOGICAL RESOURCES ASSESSMENT
The results of the analysis of existing data was used to assign the paleontological potential rankings of the SVP (2010) to the geologic units present in the Project area. These rankings are designed to inform the development of appropriate mitigation measures for the protection of paleontological resources and are widely accepted as industry standards in paleontological mitigation (Murphey et al. 2019; Scott and Springer 2003). These rankings are as follows:
High Potential. Rock units from which vertebrate or significant invertebrate, plant, or trace fossils have been recovered are considered to have a high potential for containing additional significant paleontological resources. Rock units classified as having high potential for producing paleontological resources include, but are not limited to, sedimentary formations that are temporally or lithologically suitable for the preservation of fossils (e. g., middle Holocene and older, fine-grained fluvial sandstones, argillaceous and carbonate-rich paleosols, cross-bedded point bar sandstones, fine-grained marine sandstones, etc.), some volcaniclastic formations (e. g., ashes or tephras), and some low-grade metamorphic rocks.
Undetermined Potential. Rock units for which little information is available in the literature or museum records concerning their paleontological content, geologic age, and depositional environment are considered to have undetermined potential. Further study and field work is necessary to determine if these rock units have high or low potential to contain significant paleontological resources.
Low Potential. Rock units that are poorly represented by fossil specimens in institutional collections or, based on general scientific consensus, only preserve fossils in rare circumstances (e. g., basalt flows or Recent colluvium) have low paleontological potential.
No Potential. Some rock units have no potential to contain significant paleontological resources, for instance high-grade metamorphic rocks (such as gneisses and schists) and plutonic igneous rocks (such as granites and diorites).
5.3 PALEONTOLOGICAL RESOURCES IMPACTS ASSESSMENT
Impacts to paleontological resources can be classified as direct, indirect, or cumulative. Impacts can also be considered as adverse impacts or as positive impacts. Direct adverse impacts on paleontological resources are the result of damage or destruction of these nonrenewable resources by surface disturbing actions including construction excavations. Therefore, in areas that contain paleontologically sensitive geologic units, ground disturbance has the potential to adversely impact paleontological resources, by damaging or destroying them and rendering them permanently unavailable to science and society.
Positive direct impacts, however, may result when paleontological resources are identified during construction and the appropriately documented and salvaged, thus ensuring the specimens are protected for future study and education.
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Indirect adverse impacts typically include those effects which result from the continuing implementation of management decisions and resulting activities, including normal ongoing operations of facilities constructed within a given project area. They also occur as the result of the construction of new roads and trails in areas that were previously less accessible. This increases public access and therefore increases the likelihood of the loss of paleontological resources through vandalism and unlawful collecting, thus constituting an adverse indirect impact. Human activities that increase erosion also cause indirect impacts to surface and subsurface fossils as the result of exposure, transport, weathering, and reburial.
Cumulative adverse impacts can result from incrementally minor but collectively significant actions taking place over time. The incremental loss of paleontological resources over time from construction-related surface disturbance or vandalism and unlawful collection would represent a significant cumulative adverse impact, because it would result in the destruction of non-renewable paleontological resources and the associated irretrievable loss of scientific information.
Positive impacts can result from the preservation of significant paleontological resources identified during construction, a direct impact, or following Project activities, an indirect impact. By successfully identifying, salvaging, and curating significant paleontological resources in a federally accredited repository, they are preserved in perpetuity and may contribute to scientific understanding and public education and awareness.
The impact assessment conducted here takes into consideration all planned project activities in terms of aerial and subsurface extents, including the possibility of subsurface geologic units having a different paleontological potential than surficial units. For example, younger surficial sediments (alluvium, lacustrine, eolian, etc.) have low potential to preserve fossil resources due to their age; yet sediments increase in age with depth and so these surficial deposits often overly older units that have high paleontological potential. In areas with this underlying geologic setting surficial work may be of low risk for impacting paleontological resources while activities that require excavations below the depth of the surficial deposits would be at greater risk of impacting paleontological resources. For this reason, the impact assessment takes into consideration both the surface and subsurface geology and is tailored to Project activities.
6.0 RESULTS
The results of the paleontological potential and impacts assessments are described below, with the results of the records search from the LACM summarized in Table 1 and the summary of the geology of the Project area in Table 2.
6.1 PROJECT AREA GEOLOGY
Geologic mapping by Morton and Miller (2006) indicates the surface of the Project area consists of young alluvial fan deposits, with very old alluvial fan deposits mapped at the surface approximately 0.1 miles
DRAFT PALEONTOLOGICAL RESOURCE ASSESSMENT FOR THE PEDLEY SPREADING GROUNDS – POND ENHANCEMENTS PROJECT, LOS ANGELES COUNTY, CALIFORNIA
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west of the Project area, and therefore likely present in the subsurface of the Project area (Figure 3).
These geologic units range in age from the Holocene to the Pleistocene and are described below.
Young Alluvial Fan Deposits (Qyf in Figure 3). Young alluvial fan deposits are found across the entire Project area. These sediments consist of varying proportions of unconsolidated to slightly consolidated boulder, cobble, gravel, sand, and silt (Morton and Miller 2006). Alluvial sediments represent terrestrial deposition of water-transported sediments from the surrounding highlands. These sediments are relatively young in age, dating from the Holocene to the late Pleistocene, increasing with depth, and likely overlie very old alluvial fan deposits, described below. As defined by the SVP (2010), paleontological resources must be over 5,000 years in age, corresponding to the middle part of the Holocene. Therefore, young alluvial fan deposits are not old enough at the surface to preserve fossils, but as sediments increase in age with depth, older deeper layers of this unit are of an age to preserve fossils.
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Figure 3. Geologic map of the Project area
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Very Old Alluvial Fan Deposits (Qvof in Figure 3). Give the proximity of surficial outcrops, very old alluvial fan deposits may occur at an undetermined depth in the subsurface of the Project area. Morton and Miller (2006) show these sediments on the surface approximately 0.1 miles to the southwest of the Project area at Indian Hill. These sediments are described as moderately to well-consolidated boulder, cobble, gravel, sand, and silt deposits issued from confined canyons or valleys (Morton and Miller 2006).
They represent a similar depositional environment as described above for young alluvial fan deposits, but are older, dating from the middle to early Pleistocene (Morton and Miller 2006). While this is not a formal chronostratigraphic unit, these deposits are likely 120,000 to 2.58 Ma (International Commission on Stratigraphy 2022). As such, these sediments are of an age to preserve fossils.
6.2 PROJECT AREA PALEONTOLOGY
Early Holocene and Pleistocene-aged alluvial sediments such as those present in the subsurface of the Project area have a documented history of fossil preservation in the Los Angeles Basin and across Southern California.
The locality search from the LACM indicates there are several fossil localities known to the museum in the vicinity of the Project area from alluvial sediments similar to those that are present in the subsurface of the Project area (Table 1; Appendix A). The closest of these is from Chino, approximately 8.7 miles southwest of the Project area, where horse and camel fossils were found between 15 and 20 feet below ground surface (bgs) (LACM 2022). Three other localities are known in Chino Hills consisting of fossil remains of ground sloth, a member of the elephant family, camel, and horses (LACM 2022). Other localities are known from Eastvale, where a mammoth was preserved, and Corona, where a member of the cow family was preserved (LACM 2022). While the depths of many of these finds are unknown, others range from 9 fee to 100 feet bgs (LACM 2022). While precise lithologic and location data are not available in the UCMP database, a search indicates they do have localities likely from terrestrial sediments similar to those in the Project area, including horse specimens recovered from Athens on the Hill in southern Los Angeles, the Los Angeles Brickyard near downtown, pine fossils from Century City, a bison from Montebello, and others (UCMP 2022).
Additionally, a review of the scientific literature indicates that older alluvial sediments such as those likely present in the subsurface of the Project area are well known for the preservation of fossils representing a rich Ice Age fauna. These include animals still found in North America today, such as deer, bison, sheep, and horses; creatures no longer found in North America, such as camels, lions, cheetahs, and sloths; and extinct creatures such as mammoths, dire wolves, and saber-toothed cats (Jefferson 1991 a and b, Graham and Lundelius 1994, McDonald and Jefferson 2008, Miller 1971, Reynolds and Reynolds 1991).
In addition to these iconic large animals, a wide variety of small animals can be preserved, including reptiles such as frogs, salamanders, snakes, and birds (Collins et al. 2018, Gilbert 1998, Jones et al. 2008, Miller 1941). These fossils are important for recreating the history of Southern California, in particular studying climate change (e.g., Roy et al. 1996), extinction (e.g., Barnosky et al. 2004, Jones et al. 2008, Sandom et al. 2014, Scott 2010), and paleoecology (e.g., Connin et al. 1998, Trayler et al. 2015).
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Given the extensive record of significant fossils recovered from early Holocene and Pleistocene-aged terrestrial sediments, the alluvium in the Project area is here assessed as having low-to-high paleontological potential, increasing with depth. The exact depth at which this transition occurs cannot be determined precisely in the Project area; however, the records of the LACM and reports in the scientific literature (i.e., Jefferson 1991 a and b, Reynold and Reynolds 1991) indicate depths of as little as 5 feet to 10 feet bgs in the region may yield paleontological resources.
Table 1 Summary of the records search from the LACM
Locality Number Age Taxa Approximate Location Depth
LACM VP 4619 Pleistocene Mammoth ( Mammuthus) Eastvale, CA; 13 miles southeast of Project area
100 feet
bgs
LACM VP 7811 Pleistocene Whip snake ( Masticophis) Chino Valley, CA; 8.7 miles south of Project area
9 to 11
feet bgs
LACM VP 1207 Pleistocene Bovidae Corona, CA; 17 miles
southeast of Project area
Unknown
LACM VP 7268,
7271
Pleistocene Horse ( Equus) Chino Hills, CA; 8 miles
southwest of Project area
Unknown
LACM VP 7508 Pleistocene Ground sloth
(Nothrotheriops), elephant
family (Proboscidea),
horse (Equus)
Chino Hills, CA; 8 miles
southwest of Project area
Unknown
LACM VP 1728 Pleistocene Horse (Equus), camel
(Camelops)
Chino, CA; 8.4 miles
southwest of Project area
15 to 20
feet bgs
Table 2 Paleontological potential of geologic units within the Project area Geologic Unit Age Occurrence within
Project area
Paleontological
Potential*
Young alluvial fan deposits Holocene to late Pleistocene Entire surface Low-to-High, increasing with
depth
Very old alluvial fan deposits Middle to early Pleistocene Likely in the subsurface at unknown depth
High
*ranking based on the SVP (2010) classifications
6.3 PALEONTOLOGICAL RESOURCES IMPACTS ASSESSMENT
The paleontological potential assessment presented above indicates that the Project area includes young alluvial fan deposits mapped at the surface, which have low-to-high paleontological potential, increasing with depth, and very old alluvial fan deposits, which have high paleontological potential, likely present in the subsurface of the Project area at unknown depth. Should paleontological resources preserved in these units be impacted by Project activities it would constitute a direct adverse impact under CEQA.
Therefore, an impacts assessment was conducted to evaluate planned Project activities and their likelihood to pose an adverse impact to paleontological resources.
DRAFT PALEONTOLOGICAL RESOURCE ASSESSMENT FOR THE PEDLEY SPREADING GROUNDS – POND ENHANCEMENTS PROJECT, LOS ANGELES COUNTY, CALIFORNIA recommendations and management considerations
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The Project plans to regrade a series of existing pond basins, reoperate the 30-inch storm drain, and upgrades to Chaparral Park. This work will entail a variety of ground disturbing activities, the exact details of which are not finalized at present. Following construction, operations and maintenance activities are not anticipated to include ground disturbance in previously undisturbed areas.
Of these activities, those that require ground disturbance that will extend into geologic units with high paleontological potential are at risk of posing a direct adverse impact to paleontological resources. High potential sediments may be present as shallowly as 5 feet to 10 feet bgs in the Project area. The pond basins have already been excavated to depths of at least 20 feet bgs, and so any additional grading in these basins is anticipated to impact high potential sediments. Other ground disturbing activities such as potholing for utilities or to install culverts only risk impacting paleontological resources if they exceed 5 feet bgs in depth.
Because this Project has the potential to cause direct adverse impacts to paleontological resources, Stantec has developed recommendations for mitigating these impacts, presented below.
7.0 RECOMMENDATIONS AND MANAGEMENT
CONSIDERATIONS
As part of the current paleontological assessment, a records search from the LACM and a review of geologic mapping and the scientific literature were conducted in order to assess the potential of the geologic units in the Project area to preserve paleontological resources. The results of this assessment show that the following geologic units are present in the project area:
Young alluvial fan deposits: low-to-high paleo ntological potential, increasing with depth; Very old alluvial fan deposits: high paleontological potential.
Project activities may include grading to deepen and widen existing pond basins and other unspecified types of ground disturbance. This assessment indicates that geologic units with high paleontological potential are present in the subsurface at depths exceeding approximately 5 feet throughout the Project area. Should project-related activities encounter paleontological resources, the damage or destruction of those resources would constitute an adverse impact under CEQA. In order to adhere to State and City guidelines regarding paleontological resources, Stantec recommends the following:
1. A paleontologist meeting profes sional standards as defined by Murphey et al. (2019) shall be retained as the Project Paleontologist to oversee all aspects of paleontological mitigation, including the development and implementation of a Paleontological Monitoring and Mitigation Plan (PMMP) tailored to the Project plans that provides for paleontological monitoring of earthwork and ground disturbing activities into undisturbed geologic units with high paleontological potential to be conducted by a paleontological monitor meeting industry standards
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REFERENCES
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(Murphey et al. 2019). A final monitoring report summarizing the results of the monitoring program should be prepared at the conclusion of Project ground disturbance.
2. The PMMP should include provisions for a Wo rkers’ Environmental Awareness Program training that communicates requirements and procedures for the inadvertent discovery of paleontological resources during construction, to be delivered by the paleontological monitor to the construction crew prior to the onset of ground disturbance.
3. The PMMP should provide for full time paleontological monitoring of grading in the existing basins at any depth, and of other ground disturbing activities that exceed 5 feet in depth below the natural ground surface in previously undisturbed sediments. The Project Paleontologist may reduce the frequency of monitoring or spot checks should subsurface conditions indicate low paleontological potential.
4. Should a potential paleontological resource be id entified in the Project area, whether by the monitor or a member of the construction crew, work should halt in a safe radius around the find (usually 50 feet) until the Project Paleontologist can assess the find and, if significant, salvage the fossil for laboratory preparation and curation at the LACM.
These recommendations meet the standards of the SVP (2010) and conform to industry best practices (e.g., Murphey et al. 2019; Scott and Springer 2003) Based on the findings in this study the proposed Project will not cause an adverse impact to paleontological resources with the incorporation of the above mitigation recommendations. Therefore, no additional paleontological resources studies are recommended or required at this time. Should the Project location or plans change, this assessment will need to be revised to address those changes.
8.0 REFERENCES
Barnosky, A., C. Bell, S. Emslie, H. T. Goodwin, J. Mead, C. Repenning, E. Scott, and A. Shabel. 2004.
Exceptional record of mid-Pleistocene vertebrates helps differentiate climatic from anthropogenic ecosystem perturbations. Proceedings of the National Academy of Sciences 101: 9297-9302.
City of Pomona. 2014. Pomona General Plan. Available at:
https://www.pomonaca.gov/government/departments/development-services/planning- division/general-plan. Accessed on November 11, 2022.
Collins, P., D. Guthrie, E. Whistler, R. Vellanoweth, and J. Erlandson. 2018. Terminal Pleistocene- Holocene avifauna of San Miguel and Santa Rosa Islands: identifications of previously unidentified avian remains recovered from fossil sites and prehistoric cave deposits. BioOne Complete 78: 370-403.
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REFERENCES
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Connin, S., J. Betancourt, and J. Quade. 1998. Late Pleistocene C4 plant dominance and summer rainfall in the Southwestern United States from isotopic study of herbivore teeth. Quaternary Research 50: 179-193.
Critelli, S. P. Rumelhart, and R. Ingersoll, 1995. Petrofacies and provenance of the Puente Formation (middle to upper Miocene), Los Angeles Basin, southern California: implications for rapid uplift and accumulation rates. Journal of Sedimentary Research A65: 656-667.
Eisentraut, P. and J. Cooper. 2002. Development of a model curation program for Orange County’s archaeological and paleontological collections. Prepared by California State University, Fullerton and submitted to the County of Orange Public Facilities and Resources Department/Harbors, Parks and Beaches (PFRD/HPB).
Gilbert, M. 1998. Habitats in the Los Angeles Basin in the Late Pleistocene, with emphasis on the fossil reptiles and amphibians from the La Habra Formation, Orange County, California. California State University, Fullerton ProQuest Dissertations Publishing, Master’s Thesis.
Graham, R.W., and E.L. Lundelius. 1994. FAUNMAP: A database documenting the late Quaternary distributions of mammal species in the United States. Illinois State Museum Scientific Papers XXV(1).
Harden, D. 2004. California Geology, 2nd edition. Pearson Prentice Hall, 552 p.
Ingersoll, R. V. and P. E. Rumelhart. 1999. Three-stage basin evolution of the Los Angeles basin, southern California. Geology 27: 593-596.
Jefferson, G.T. 1991a. A catalogue of Late Quaternary Vertebrates from California: Part One, nonmarine lower vertebrate and avian taxa. Natural History Museum of Los Angeles County Technical Reports No. 5.
--------. 1991b. A catalogue of Late Quaternary Vertebrates from California: Part Two, Mammals. Natural History Museum of Los Angeles County Technical Reports No. 7.
Jones, T., J. Porcasi, J. Erlandson, H. Dallas, T. Wake, and R. Schwaderer. 2008. The protracted Holocene extinction of California’s flightless sea duck (Chendytes lawi) and its implications for the Pleistocene overkill hypothesis. Proceedings of the National Academy of Science 105: 4105- 4108.
Kimbrough, D. L., T. E. Moore, M. Grove, R. G. Gastil A. Ortega-Rivera, and C. M. Fanning. 2001.
Forearc-basin sedimentary response to rapid Late Cretaceous batholith emplacement in the Peninsular Ranges of southern and Baja California. Geology 29: 491-494.
McDonald, H. G. and G. T. Jefferson. 2008. Distribution of Pleistocene Nothrotheriops (Xenartha, Nothrotheridae) in North America. In: Wang, X. and L. Barnes, eds., Geology and Vertebrate
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REFERENCES
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Paleontology of Western and Southern North America. Natural History Museum of Los Angeles County Science Series 41: 313-331.
Miller, W. E. 1941. A new fossil bird locality. Condor 44:283-284. --------. 1971. Pleistocene vertebrates of the Los Angeles Basin and vicinity: exclusive of Rancho La Brea.
Los Angeles County Museum of Natural History Technical Reports, No. 10.
Morton, D. M. and F. K. Miller. 2006. Geologic map of the San Bernardino and Santa Ana 30’ × 60’ quadrangles, California. U.S. Geological Survey Open-File Report 2006-1217. Scale 1:100,000.
Murphey, P., and D. Daitch. 2007. Paleontological Overview of Oil Shale and Tar Sands Areas in Colorado, Utah, and Wyoming. U.S. Department of Energy, Argonne National Laboratory report prepared for the U.S. Department of Interior Bureau of Land Management, p. 468 and 6 maps (scale 1:500,000).
Murphey, P., G. Knauss, L. Fisk, T. Demere, and R. Reynolds. 2019. Best practices in mitigation paleontology. Proceedings of the San Diego Society of Natural History 47: 43 pp.
Natural History Museum of Los Angeles County (LACM). 2022. Paleontological resources for the Pedley Spreading Grounds, Project #184031542). Email response received on October 30, 2022.
Norris, R., and R. Webb. 1990. Geology of California. John Wiley and Sons, Inc., New York.
Reynolds, R. E., and R. L. Reynolds. 1991. The Pleistocene beneath our feet: near-surface Pleistocene fossils in inland southern California basins; pp. 41-43 in M. O. Woodburne, R. E. Reynolds, and D. P. Whistler (eds.) Inland Southern California: the last 70 million years. San Bernardino County Museum Association, Redlands, California.
Roy, K., J. Valentine, D. Jablonski, and S. Kidwell. 1996. Scales of climatic variability and time averaging in Pleistocene biotas: implications for ecology and evolution. Trends in Ecology and Evolution 11:
458-463.
Sandom, C., S. Faurby, B. Sandel, and J.-C. Svenning. 2014. Global late Quaternary megafauna extinctions linked to humans, not climate change. Proceedings of the Royal Society B 281, 9 pp.
Scott, E. 2010. Extinctions, scenarios, and assumptions: Changes in latest Pleistocene large herbivore abundance and distribution in western North America. Quaternary International 217: 225-239.
Scott, E., and K. Springer. 2003. CEQA and fossil preservation in southern California. The Environmental Monitor 4-10.
Society of Vertebrate Paleontology (SVP). 2010. Standard Procedures for the assessment and Mitigation of adverse impacts to paleontological resources. Available at https://vertpaleo.org/wp- content/uploads/2021/01/SVP_Impact_Mitigation_Guidelines.pdf; Accessed on November 9, 2022.
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REFERENCES
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Trayler, R.B., Dundas, R.G., Fox-Dobbs, K. and Van De Water, P.K. 2015. Inland California during the Pleistocene—Megafaunal stable isotope re cords reveal new paleoecological and paleoenvironmental insights. Palaeogeography, Palaeoclimatology, Palaeoecology 437: 132-140.
Yerkes, R. F., T. H. McCulloh, J. E. Schollhamer, and J. G. Vedder. 1965. Geology of the Los Angeles Basin – an introduction. United States Geological Survey Professional Paper 420-A.
APPENDIX A
Natural History Museum of Los Angeles County
Paleontological Records Search Results
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