Geologic History

Geologists who studied The Irvine Ranch recognized a number of unique and rare features -- including fossils of hadrosaurian, or "duckbilled," dinosaurs in the Blind Canyon area. On a large scale, the land is an outstanding illustration of the complicated and unique geologic history of the southwestern margin of the continental United States. The exceptionally wide spectrum of rock types and fossils captures changing landscapes and evolutionary events with remarkable completeness for a span of 80 million years. The terrain ranges from picturesque coastline subject to modern erosion and other natural processes to rugged, uplifted mountains where the geologic history of Southern California from the late Cretaceous period (65 million to 80 million years ago) to the late Pleistocene period (less than 1 million years ago) is beautifully exposed and largely intact.