Thread by @mikamckinnon

Fort Cronkhite, California is one of my fav beaches.

Every beach has many geologic processes are just waiting for you to notice them, but Cronkhite takes you on a geologic tour of the Bay Area.

Here’s the cliff bluff of the beach, my Earth Ring (with or without hand) for scale.

Can you see thebeds, layered lines of rock deposited at the same same? See the pebbles?

Those cliffs erode, relinquishing their pebbles on to the beach.

The pebbles were originally from all over the ancient Bay Area, giving us a hand-sized geologic sample of the region.

As you get farther from the cliffs, the pebbles get smaller and smaller until they’re tiny grains of sand.