Sunday, March 21, 2021

Finds at the fossil beach

 A friend sent me a text last weekend asking if I wanted to join her and her family at a beach near our house to look for fossils. It was a beautiful day, it had been two and a half weeks since my second vaccine shot, and I had not seen Max for over six months, so I was keen to join them. But at the same time I was thinking, fossils in Capitola?! In spite of being a marine ecologist, I spend very little time at the beach. When I was working on the coast, my job would either take me to rocky intertidal areas or kelp forests. The geology of Monterey Bay is such that most of the rocky intertidal areas are start at the northern and southern ends of the Bay, with a big crescent of beach in the middle. As a result, I have spent very little time in the "crescent" of the Monterey Bay shoreline. 

When I met up with Max and family, she told me that Capitola Beach was listed as one of the best places in coastal California to find fossils. I was surprised to learn this after living here for nearly 20 years. We threaded our way through the throngs of beach-goers on the esplanade (none of us had been around that many people in over a year - it was weird) and headed to the southeast along the cliffs. Fortunately there were very few people along the beach, so we set off to search for fossils. 

We didn't have to search very long or very hard before we came upon boulders covered in shells. The walls of the cliffs are sandstone, a soft, very erodible rock that had multiple horizontal layers of shells embedded in it, like layers of a cake. The fossils are all contained in the Purisima Formation, which preserved fossils from the Pliocene era between 2.5 and 5.5 million years ago.The cliffs are very unstable and as they erode, they provide a steady stream of rocks with fossils to the beach below. As we walked along the beach marveling at the gazillions of shells, we started finding bones. BIG bones. Pelvic girdles, vertebrae, ribs, appendages, all likely from a combination of whales, dolphins, seals, and fish. It was amazing! What a fun treat to find a new place to explore in our own backyard. 

bands of shells (the white stripes) in the sandstone cliffs

boulders fall off the cliff, bringing the fossils to eye level

pelvis

ribs?

clam

spine - looks kind of fishy? 

vertebrae, likely lumbar because of the long "wings"

two and a half foot long bone - rib? part of a skull?

lots of shells

beach cliffs hiding many treasures

If you get a chance to go explore, head to the beach at near low tide and enjoy imagining who was swimming in the ocean millions of years ago.