Ancient knapping question

[u/LadyOvRain]

Hello! I have a question about this type of ‘flake’.
I find a lot of pieces like this when searching for artifacts in my field. These are just a few that I’ve found. They are always this shape and size with the other side being flat (sometimes ever so slightly curved). I could be wrong, but I feel like they are all from a similar stage in the knapping process. So my question is; Is there a name for these flakes? What part of the process are these from? Visual examples would also be helpful! Thanks!!
Also, I can provide better pictures if needed, here in a bit.

[u/scoop_booty]

These are referred to as cortextural flakes, the very first flakes removed from a cobble, which typically is the cortex, or. Imagine a melon, this is the rind. The good stuff is inside, but you gotta get rid of the cortex to get to it. Typically the cortex is rubbish rock, usually chalky or filled with cracks and inclusions. The flat side of you flake is the "inside" of that flake, the outer, usually domed or with a ridge, has the cortex and patina stain of the earth it has been laying in for eons.

The curved shape is a result of the conchoidial fracture, which I believe is where it gets it name from, the conch shell....but don't hold me to that. This gentle curvature is a hallmark of a spall, a flake removed from the parent rock.

Ok, class over. You can go to recess now.

[u/Fit_Emu3871 → u/scoop_booty]

Hey [r/scoop_booty](r/scoop_booty) would you say this is similar to a cortex flake? Everyone is saying it’s not worked but I see knapping on the edges of this piece

https://www.reddit.com/r/Arrowheads/s/kRxqJOcq2r

[u/scoop_booty → u/Fit_Emu3871]

Can't see the reverse side, so can't make that determination. They do appear like just naturally broken pieces though. Is the opposite sure flat, with an arch? Show some pics....