The Conveyor Belt

Beach Cobbles, Lincoln Park, Seattle

One of the best rockhounding locations in the Pacific Northwest is so close...that I can see it from my house. Seriously, one of my favorite rock-hunting spots is along any of the cobble beaches along the shores of Puget Sound. You can never tell what you might find out there including a variety of jaspers, agates, petrified wood, and just some beautiful stones of unknown origin. In fact, almost all of the rocks are from somewhere else.  Why?  Because almost all are leftovers from the Ice Age, when a glacier 5000 feet thick carved Puget Sound, and, like a gigantic conveyor belt, carried rock from a hundred locations to the north and dumped them here.

I find this fascinating. Some of the rocks I pick up along the beach may have been plucked from an outcrop in British Columbia, or have fallen off a peak in the North Cascades.  There are igneous rocks, metamorphics, and, of course sedimentary rocks as well: to be honest, I have no idea what half of them are!  Here are just a few samples from the beaches here, mostly jaspers, and at least one petrified wood.

All in a Day's collection, Puget Sound

Where are they from?  Who knows? Yes, sometimes it's a little frustrating to find a real stunner on the beach, knowing that you probably won't see another one, and with no clue where it originated. (It is rare, in fact, to see two rocks that appear to have come from the same locality.)

Having said that, most are beautifully rounded, making tumbling a snap. No surprise: they've been getting tumbled in the ocean for 10,000 years!