An early Pleistocene closed-cone pine forest at Costa Mesa, southern California

Fossils of Cupressus macrocarpa Gordon, Pinus muricata Don, Pinus radiata Don, Pinus remorata Mason, and Quercus macdonaldii Greene have been recovered from an early Pleistocene deposit (ca. 1 Ma) from Costa Mesa, coastal southern California. All these species have very restricted distributions today but were more widely distributed during the late Cenozoic. The paleoclimate at Costa Mesa probably was similar to that now at Monterey 560 km north. Colder climate is indicated by the record of Pleistocene marine megafossils and by the composition of the early Pleistocene fossil floras in coastal and interior southern California.