Environmental Consulting

Baker Ranch Cultural Resources Monitoring | Lake Forest, CA

Shea Homes


CEQA Documentation (IS/MND and Addenda)
Phase I Records Search and Survey Report
Native American Consultation
Phase II Resource Evaluation Report
Phase IV Monitoring Mitigation Report
Construction Monitoring
Fossil Salvage and Identification
Fossil Preparation for Curation

Archaeological and Paleontological Resources Investigations

BonTerra Psomas is currently providing cultural resources mitigation and monitoring services for Baker Ranch, a master-planned community of 2,379 residential units and 25,000 SF of commercial development. The project implements mitigation adopted as a part of the City of Lake Forest Opportunities Study Program Environmental Impact Report (EIR). As part of the EIR effort, BonTerra Psomas completed a Phase I assessment and Phase II testing and evaluation of several sites prior to construction.

Archaeological, Native American, and paleontological monitoring was required during grading activities because of the known presence of archaeological sites, and grading occurred in fossil-bearing soils (specifically the Oso Sands Member of the Capistrano Formation, which dates to 8–12 million years ago). This monitoring has been ongoing since January 2013 and will be split into three phases. During Phase One, a large collection of marine mammal fossils—including whales (Balaenopteridae), fur seals (Thalassoleon), sea cows (Dugongidae), dolphin, walrus (Imagotaria), and fishes such as shark, salmon (Oncorhynchus), and halibut (Paralichthys)—was recovered by BonTerra Psomas field personnel. Another large collection is expected to be recovered during Phases Two and Three.

Since large collections from the Oso Sands Formation are uncommon, these discoveries will contribute to a better understanding of life during the Miocene Epoch in the Los Angeles Basin. At the conclusion of the project, the fossils will be transferred to the John D. Cooper Archaeological and Paleontological Center in Santa Ana, where they will be curated in perpetuity and made available for study by paleontological researchers.