We had a goal of finding one object that was not familiar and that we didn’t recall seeing in our field guides. I knew we had a winner when Jon called out dramatically for me to come and see something.
The reflection of the sunrise is putting on a white shine, the natural eye saw a black/dark green color, glossy, like a fresh tar.
As you may notice, the tubes are several shapes and thicknesses. There are smaller colonies growing as well. They were mostly growing on the vertical slope of a rock, yet Jon found a colony covering the horizontal top of an outcropping at the water’s edge.
I posted the photos on Facebook asking for my friends to help me identify it. I spent a couple of hours looking through several field guides and googling descriptives like Looks Like Brains, Looks like Oil, Tube Like, Soft, Smooth, Black, Zone 4 or 3, Low Tide & Tide Pools. Many people thought it was tar or oil. But it was firm, soft to the touch, sponge like. One friend was sure it was Whale Poop. 
My friend Misti was the winner –Green Spongy Cushion or Codium setchellii – Description by Jan Holmes – “Like C. fragile, Codium setchellii patches are composed of a single cell made of interwoven filaments packed with nuclei and chloroplasts. Individual dark green or greenish black cushions are soft and sponge-like up to 2 cm (3/4 inch) thick and 25 cm (10 inches) in diameter. It can be found with C fragile on high energy beaches in the lower intertidal.”
Single Cell? That is just crazy. These patches are really large! I also emailed a contact at the Hatfield Marine Science Center asking the identification of this mystery object – and then sent him Misti’s guess – and he confirmed that it is Codium Setchellii. Exciting.
I think this would also qualify for the Handbook of Nature Study’s Extraordinary in the Ordinary Newsletter Challenge she put up this week. We’ll be notebooking this find in our seatwork time today for sure!
We have been enjoying the low tides this week pulled back by the Super Moon. I’ve run my camera battery dry twice (300 photos each). It’s hard to pull out what I might think you’d like to see. If you are studying Low Tide Zone 4 Tide Pools, and are looking for an object, I probably have a photo! I gathered up a few posts based on Landscapes, Animals, Plants and Fun Photos:
+Angie Wright
Pebblekeeper 
Very interesting! 🙂 Stopping by from the OHC
awesome! we live at the beach & I’m homeschooling 3 busy boys 😉 today we collected a ton of bugs (dead ones) put them in clear tape and looked at them under the microscope – they were pretty excited
I have learned more about nature and the world around me studying with my children than I ever would have thought possible. And I always loved nature and being outside and thought I knew a little something about it. 🙂 Such a neat find!
Awesome! Isn’t it great to find something you know nothing about, and then investigate until you find out?
Super cool extraordinary thing! Great find!