This is a small display of a single whale fossil (if you can have a small whale) in an out of the way corner of a shopping center in Mission Viejo California. It is located about 2 feet behind a locked gate for security. A fading display is posted up behind it. This is an example of fossils sitting beneath living rooms, pools, and golf courses in the area.
This whale fossil was discovered during grading for one of the many developments in southern Mission Viejo. The 3.5 to 3 million year old fossil came out of a section of the Capistrano Formation. It is estimated that when alive, this whale was 58 feet long and weighed 50 tons.
The Capistrano Formation is of early Pliocene and Miocene age (approximately 3 million years ago to 6 million years ago stratigraphic column) . It is made up of marine sandstone with some siltstone and mudstone. Most of the fossils in the Capistrano Formation are found in the Oso Member of the Capistrano Formation which is a white marine sandstone. 
Fossils of fish, sharks, sea lion, whales, and other marine mammals have been found in this layer of rock.
The Oso Member was deposited in a shallow marine embayment. It is possible that this embayment was a calving ground for whales and a feeding ground for sharks.
The siltstone and mudstone of the Capistrano Formation were deposited in the deep ocean shelf and ocean basins. These rocks are found closer to the shore near San Clemente and Dana Point. Similar fossils are found in these rocks as well.
Another local location that hasn’t gotten paved over is the Pectin Reef earthcache
Logging requirements:
Send me a note with :
- The text "GCZ5HR Mission Viejo Whale Fossil" on the first line
- The number of people in your group.
- From the display, send me a note with the species of whale and the modern day equivalents.
The following sources were used to generate this cache:
- County of Orange, Harbors, Beaches, & Parks; Orange County Archaeology and Paleontology Guidelines, Procedures, and Policies, unknown date, http://www.ocparks.com/uploadgraphics/OverviewFinalReport2.pdf
- USGS, National Geologic Map Database, GEOLEX database, http://ngmdb.usgs.gov/Geolex/NewUnits/unit_12482.html
- image fromGeocaching log by Kevin & Susan