Rocks In Rocks – Discovering The Cool & Wacky World Of Concretions

Oh thou art SOOooooo coooool!

Sometimes you discover something that is SO ÜBER COOL you just have to find out everything about it. This happened to me a few weeks ago as I was writing about our visit to Cape Arago and discovered this post about concretions. I had never heard about these things and was immediately intrigued. A rock that grows inside another rock? The creation of outlandish spherical bulbs of all sizes? Rocks that contain fossilized matter inside? Rocks that grow to be as big as a person? Landscapes of giant rocks that look like outer space?

OMG…this is the most totally cool thing EVER! I was hooked and absolutely, positively needed to find these things and see them for myself.

Lu & Terry pose at one of “the giants” in Fossil Point

Thus began a 2-week expedition of “concretion hunting” with some fun exploration and exciting pictures to boot. Not only have I discovered the best local hiding spots around Charleston and Shore Acres, but I’ve learnt alot more about these unusual and fun geological structures.

Concretions come in all sizes

So what exactly IS a concretion? Structurally they are compact masses of mineral matter embedded in a host rock of other matter. They typically start to form around a “nucleus” of some sort (a shell, a crab, a leaf whatever) and grow inside cracks and cavities of other rocks or get buried in sediment that then hardens. The net effect of all this is a rock within a rock….or more specifically one type of rock inside another type. Surprisingly they are actually really common, but for a non-geologist like me finding these things is akin to the discovery of chocolate sauce on ice cream -> a totally delicious revelation!

Concretions at Yoakam Point -> AWESOME!

So now that I’ve got you all hot and bothered to see them, where do you actually go to find these hidden gems? The area around Charleston & Shore Acres actually has 5 excellent spots with concretions of all sizes, two of which I discovered with my cousin and one (“the giants”) that I scoped out yesterday with our RV buddies Lu & Terry (Paint Your Landscape) who just rolled into town. They are ALL worth visiting and these are my top picks (map at bottom):

1/ “The Giants” at Fossil Point -> Humungous man-size concretions that are best seen at absolute low tide. Going north from Charleston, cross the bridge and drive ~1.8 miles along Cape Arago Hwy. Park at the first turnout on your left after Fossil Point road. Hike around the point to the south until you see the monsters. This is also a great spot to hunt fossils, as you’d expect. Be prepared for mud!

Walking around the giants at Fossil Point

Part of “the wall” at Yoakam Point

2/  ”The Wall” at Yoakam Point -> A spattering of softball-size concretions on a cool wall that juts into the ocean. These are also best seen at low tide where more of the beach is open to walking. Going south from Charleston along Cape Arago Hwy, drive past Oceanside RV Park and take the first turn-out on your right a little ways up the hill. There are several poles and the entry to a trail, but no signs. Follow the trail to the beach and go right from there to see the wall.  The beach here is also, incidently, one of the best places to get a view of closed-to-the-public Cape Arago Lighthouse.

“The line” at Simpson Beach

3/ “The Line & Seat” at Simpson Beach -> A really cool line of ground concretions and interesting wall-set big enough to sit on. Simpson Beach is reached by trail directly from Shore Acres State Park. Simply take the trail to the beach and walk to the south end to see the concretions.

All in all a good few weeks hunting with a darn good set of catches. The cool and wacky world of concretions is just as fun in person as they are in print, so if you haven’t yet been seduced by these rocks, I’d recommend letling yourself go and giving it a try. Fun, discovery and rocks to write home about. Priceless!

Beauty of giants at Fossil Point

My cuz on “the seat” at Simpson Beach in Shore Acres State Park

Hanging at Simpson Beach

One side of “the wall” at Yoakam Point

Fossils at…you guessed it Fossil Point!

A partially revealed concretion at Yoakam Point

Map of Charleston area with best concretion hunting spots

Off The Beaten Track – Rainbow Basin, Barstow, CA

The hidden Gem of Rainbow Basin

Since we were driven out early by high winds from our glorious spot in Lone Pine, our “pack” decided to wheel it out and head to shelter down south in the grand Mojave desert. We were looking for the best of the best -> solitude, beauty, views, trails. In other words a spot where no “beasts” have gone before. So, of course we took the back-road to Barstow, CA and stopped there ….. ????

Shadows of Joshua Trees in the canyon

Now those of you who know Barstow may be surprised. For those of you who don’t I’ll paint a little scene. Close your eyes and imagine if you will a desolate desert plain stretching, well…to infinity. Raise your thumb, twirl it around and plonk it randomly anywhere on this dreary landscape. Add-in several enormous truck-stops, a few sad strip-malls and an ad-hoc town and voilà, there you have it. Barstow has emerged like a single stubborn weed in a huge dusty back-yard. NO-ONE vacations at Barstow, at least no-one that I know.

So naturally that’s where we went. And naturally we found everything that we were looking for, because as everyone knows there’s a hidden gem in everything….somewhere….and right here the fabulous spot is called the Rainbow Basin.

Biking into the Miocene era...

Just ~10 miles out of Barstow on a long dirt road it rises from the desert like a diamond in the rough. Rainbow Basin is an ancient formation deposited in the middle Miocene (16-13 million years ago). Tectonic motion, compression and erosion raised the earth over many millions of years and sculpted the rock into alluring curves of mineral deposits. From neon green to deep red the layers roll like rock petals of a giant rose blossoming to enclose you completely. Add-in a sprinkling of picturesque Joshua Trees and you’ve created the painting of a masterpiece.

Some pretty country out here

And there’s more than just pretty rocks here. The site is a paleontologists dream with over 368 sites and 17 new species of mammals discovered right here including the very first record of a mastodon in California. Camping is on BLM land right in the midst of the colorful painting, surrounded by miles of hiking and biking. It’s simply stunning!

Entrance to the Rainbow Basin area

Our “pack” hunkered down within the protective rocks for several days while the winds passed by up north, enjoying pretty much complete solitude (we were literally the only folks there the first 2 days) and gorgeous surroundings. A worthy and unexpected little stop  off the beaten track….and all of it in Barstow too.

Sunset in camp

A pretty view of the rocks from the trail

Deep in Rainbow Basin

Blue sky and rainbow rocks