The Puente Formation

I asked one of my geo inspectors about the terrain of Franklin Hills and he quickly rattled off the answer.

The Puente Formation - It seemed so Museum of Science and Industry kind of knowledge and then it sparked a flash of deep thoughts. A reminder that we all live on a planet which took millions of years to form. The worry in Southern California is will it stand up to rain and erosion and hold still in an earthquake. The Geo Inspector I bring in to transactions shows up to confirm these things but it got me curious enough to research what exactly Puente Formation is. And then…

When I built an ADU at the bottom of my house and ripped out a bathroom what was exposed (in the photo) looked like a cave. Multiple layers of rock and dirt with horizontal boundaries marbelized at the edges. I don’t think I actually hit Puente dirt but it looked pre-historic. Interesting, as a reminder, that beneathe every house in Franklin Hills lies the ancient rock that supports and holds it to the ground. What exactly that Puente Formation is… keep reading.

A geological formation located in Southern California, primarily in Los Angeles County. It is composed of sedimentary rocks, primarily sandstone  deposited during the Miocene epoch [15 to 20 million years ago.] The formation is notable for its fossil-bearing layers, which contain a diverse array of fossils, including marine invertebrates, terrestrial mammals, and plant remains. These fossils provide valuable insights into the region's past environment and the evolution of its flora and fauna during the Miocene period. 

The Puente Formation is significant not only for its fossil content but also for its role in shaping the landscape of Southern California. Erosion of the formation over millions of years has contributed to the formation of the region's characteristic hills and valleys, including those found in the Los Angeles Basin.  Make it stand out