Natural clay bottom.Used to make clay pots type clay.
It started as a low spot that dried up in summer. Had been going to it since I was about 5 even though I wasn't allowed. What Mom don't know won't hurt her. I tried to dig it out with a shovel when I was maybe 10 years old. I still remember the hole being about the size of a 5 gal bucket after what seemed like hours of work. So I nagged my Dad into using his tractor and rear scrapper blade like this one:
So he starts scrapping away and I'm dreaming of fish, but pretty soon he says the clay is too hard, can't get a bite. He tells me to sit on the blade to add weight, all 70 lbs. Now these blades didn't come with 3 things:
1. A seat.
2. Seat belts.
3. Any warning labels that says "10 year old boys shouldn't be used as ballast."
I'm riding this thing like it was a Brahma bull with a hornet's nest strapped to its butt. My face is like 18" from the tractor exhaust pipe back when gasoline had all kinds of goodies in it. I knew full well if I cried Uncle the digging would stop so I stuck it out until Dad had enough.
There's lots of things I've forgotten in life. Sitting between a 4 ton tractor and a steel blade zipping along the ground and knowing if I slipped it meant being mangled, probably killed...that I remember like it was yesterday.
But it got the pond deep enough so it didn't dry up completely in summer which meant I could have fish. So it was worth it. Did take a couple of years before it changed from a dirt mud hole into a clear pond with plants. I kept a journal of the different insects and plants I'd find each day. Number of frogs, number of dead frogs I'd find each day in the spring.
Here's Google Earth's view of it today. Been more than 45 years since I was there. Lot more trees around it. I'm surprised it hasn't filled in completely.
We had lots of other mud ponds all around us that I visited often. Mine was pretty small compared to most. But it was mine.