Key Staff

  • Sherri Gust, MS, RPA

    CEO | Principal Investigator for Paleontology and Archaeology

    Ms. Gust is a Qualified Principal Paleontologist and Registered Professional Archaeologist (RPA) with more than 38 years of experience in cultural resources management and consulting in California. She manages projects throughout California and is recognized for thoughtful analysis and practical mitigation.

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  • Eric Scott, MA

    Program Manager | Principal Paleontologist

    Mr. Scott is a professional vertebrate paleontologist with over three decades of experience in paleontological mitigation, fieldwork, curation, and research. He is an emeritus paleontology curator at the San Bernardino County Museum, an adjunct instructor at California State University, San Bernardino, and a research associate of the Natural History Museum of Los Angeles County.

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  • Desireé Reneé Martinez, MA

    Principal Archaeologist

    Ms. Martinez is a Registered Professional Archaeologist (RPA ID: 17457) with 21 years of experience in archaeological fieldwork, research, and curation. She has expertise in the planning, implementation, and completion of all phases of archaeological work and has participated in archaeological investigations as a crew member, tribal monitor, and principal researcher.

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  • John Harris, PhD

    Project Manager | Practice Leader and Principal Investigator for Paleontology

    Dr. Harris is a vertebrate paleontologist with more than 40 years of experience in fieldwork, curation, and research. He is currently an emeritus chief curator at the Natural History Museum of Los Angeles County, a Visiting Associate at Caltech, an adjunct professor at the University of Utah, and an Honorary Member of the Society of Vertebrate Paleontology.

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  • Kimberly Scott, MS

    Principal Investigator for Paleontology | Field and Lab Director | Geologist

    Ms. Scott is a qualified Principal Paleontologist and Sedimentary Geologist with more than 20 years of experience in California paleontology. She meets the professional standards set by the Society of Vertebrate Paleontology and Caltrans for Principal Investigator in Paleontology and is listed as a Principal Investigator on Cogstone’s Bureau of Land Management (BLM) permit.

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  • Molly Valasik, MA, RPA

    Principal Investigator| Cross-Trained Paleontologist | GIS Analyst

    Ms. Valasik is a Registered Professional Archaeologist (RPA) with eight years of professional field and academic research experience. She is a skilled professional who is well-versed in the compliance procedures of CEQA and Section 106 of the NHPA and regularly prepares cultural resources assessment reports for a variety of federal, state, and local agencies throughout California.

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  • André Simmons, MA, RPA

    Principal Investigator | Cross-Trained Paleontologist | GIS Manager

    Mr. Simmons is a Registered Professional Archaeologist (RPA) and cross-trained paleontologist with eight years of field experience in survey, monitoring, faunal analysis, and excavation. He exceeds the qualifications required by the Secretary of the Interior’s Standards and Guidelines for Archaeology and Historic Preservation.

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  • Tim Spillane, MA, RPA

    Principal Investigator| Cross-Trained Paleontologist | GIS Analyst

    Mr. Spillane is a Registered Professional Archaeologist (RPA) with more than eight years of experience working with agencies in the public and private sectors on Cultural Resource Management (CRM) projects, developing particular expertise in the historic and prehistoric archaeology of the San Francisco Bay Area and larger Northern California Region.

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  • Ashley M. Leger, Ph.D.

    Field Director | Paleontologist | Geologist

    Dr. Leger is a qualified geologist and paleontologist with over 9 years of experience in paleontology. Specializing in Pleistocene megafauna, Dr. Leger is a leading expert in extinct proboscidean crania, but also has experience ranging from the tiniest of marine microfaunas to the largest of marine reptiles.

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  • Holly Duke, BA

    Archaeologist | Cross-Trained Paleontologist | Laboratory and Data Manager

    Ms. Duke is a qualified archaeologist and cross-trained paleontologist with four years of experience in survey, monitoring, excavation, and the identification of human and faunal skeletal remains.

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