Beach Cannonballs

Concretion, Strait of Juan de Fuca, Washington

Along many of the beaches of the Straits of Juan de Fuca, these striking stone eggs (and spheres and even weirder shapes) weather out of the siltstone cliffs. They are concretions, composed of cemented sediments that grow within softer existing strata. They sometimes form around hard objects: including other stones or in the most exciting cases, around fossil animals like crabs.

I found this one (about 9" tall) on a recent trip out to the straits, and I brought it home to break open with my grandson - with the hope that it would reveal something interesting inside. The first challenge, of course, was simply breaking the thing open. After failing to make a dent with my rock hammer, we resorted to copying our neighborhood crows...and tossed it off our deck onto the street.  Bingo!

It broke, of course, but we didn't find anything obvious inside. Too bad.  Still, I'm pretty sure Theo thought the coolest part was just busting it open... 

Broken open - no Fossils