When I was a kid.
Back in the sixties.
Dinosaurs walked the streets of Shreveport.
etc.

You'd see lots of cylinders that looked sort of like concrete. They were about 4 inches in diameter, about 8 inches long. People would use them for things like edging a lawn or flower bed. We kids thought they were cores you'd get when drilling an oil well. i.e. it's an intact chunk of what the rock under the earth looked like.

Now that I know more about the way drilling is done, that doesn't seem very likely.

Does anyone else remember what I'm talking about, and what they really were?

I've heard of taking core samples. Do they actually do that very often down into rock strata around here? I believe that the normal drilling practice grinds the rock into chips and flushes it out with drilling mud. How would you do something like this? I understand using a hole drill, but how do you get the core back to the surface?

Do they tend to recover rock chips from the mud for study?

How big are the pieces of rock that come up with the mud?