The City of Lake Forest proposed a new sports and recreation complex on a 90-acre parcel that included the construction of six baseball/softball fields, up to five soccer fields, playgrounds, hard courts, an amphitheater, and a 30,000-square-foot recreation center. Under CEQA, the City of Lake Forest's EIR identified potential impacts to fossil resources likely present at the site. BFSA was retained by the City to fulfill the requirements specified by the EIR to mitigate potential impacts to fossil resources. At stake was the six-million-year-old Oso Member of the late Miocene Capristrano Formation, one of the most fossiliferous geologic units in coastal southern California, which is famous for yielding the well-preserved remains of a variety of extinct whales, sea cows, pinnipeds, fish, and sharks. Extensive mass grading for future playing fields and sports facilities exposed over a hundred feet of sandstone stratigraphy. As a result, 98 fossil localities were recovered, mostly by plaster-and-burlap methods, and are represented by more than 150 bones and teeth of past marine life. These include bones from right whales, rorqual whales, pygmy baleen whales (considered rare), sperm whales, sea cows, flounders, and saber-toothed salmon, as well as, unusually, the leg bone of a camel.