Do you ever think much about what clay really is?
A while ago, we were at Bald Head Island, NC and spent some time on the beach. I enjoy walking on the beach and looking for interesting shells, etc. Something unusual caught my attention this time. A moist, brown/grey lump, roughly oval, covered with sand.
I kept walking. Then I saw another, and another. Most people ignored them, or thought they were probably some kind of animal feces. I’m just too curious, and besides, I didn’t think it was fecal material (there were no flies). So, I picked one up. It had more weight to it than I thought by just looking at it. I broke it apart and saw uniform texture and what appeared to be clay inside the sandy coating. I started to gather these “clay” blobs… much to some other visitors’ stupefaction.
Later I was able to confirm with the Bald Head Island Conservancy that what I had found was indeed clay. Jeff Harms, the Environmental Educator, told me:
What you are finding are indeed balls of clay from the salt marsh. If you were to slog around in the present marsh you would be up to your knees in a thick layer of rich mud. Over time this mud turns into peat and clay. What’s interesting about the clay that you are finding on the beach is that it is not from the present salt marsh but rather from about 40,000 years ago when the salt marsh stood where the present beach is. Barrier islands are basically islands of sand that continuously move and shift over time. Now the island has moved enough that the old clay layer that is beneath the entire island is starting to erode by wave action offshore and wash up on our beaches. That is also why you find so many oyster shells on the beach. Oysters also grow on the marsh side (not on the ocean side) and now as the beach erodes the entire beach is covered with oyster shells from the old salt marsh. Anyway, I hope that answers your question. The shell debris and sand that you find on the outside of the clay attaches as the clay balls roll in, anything you find trapped inside would be much older.
Pretty cool. I don’t usually think about clay as the result of tremendous amounts of time and transformation. Even for the clay to be unearthed takes an enormous amount of upheaval and energy. It makes me think about the lumps of clay as a kind of history book. I still have those lumps of clay, I just have to figure out what I want to do with them. Got any ideas?