GALLAWAY, Calif. — At the southwestern edge of Mendocino County is a geological phenomenon that only appears when the tide is low. It’s a part of Schooner Gulch State Park known as 'Bowling Ball Beach.'
The sandy cliffsides offer some stark views along Highway 1, but if you take the steep staircase down the gulch and do a little rock climbing to the water’s edge, you’ll end up next to a row of spherical boulders.
The boulders are round like a bowling ball but way too big for any human to pick up, posing the question: How did they get here?
There's been a lot of speculation about how the bowling ball-shaped rocks ended up here, but State Park interpreter Steve Jahelka says it was a process of millions of years.
“As water washes over them again and again it creates these spheres,” said Jahelka.
Erosion is what’s shaping the rocks and the erosion reveals a geological phenomenon known as “concretions,” or the compression of sedimentary rocks.
“It’s pretty much compressed sand,” said Jahelka.
The towering cliffside above Bowling Ball Beach is highly compressed sand and every once in a while, pieces of the compressed sand break off and land on the beach. Then, over millions of years, the pounding waves erode the sandy rocks into smooth balls.
“If you are a geology nerd, I will tell you what, this is the place for you,” said Jahelka.
Even if you aren’t a geology nerd, there is a lot to do at the beach. If you like to explore tide pools, this is the place to do it. You may even find some cool shells.
There’s only a handful of places in the world that create rock structures like these. It’s a great place to hike and take pictures, but just remember you can only see the rocks at Bowling Ball Beach at low tide. Be sure to look at a tide chart before you go.
MORE MYSTERIOUS ROCKS ON THE BACKROADS: The rocks outside "the Box" at Fort Irwin have a story all on their own. How they get there is a mystery.