Flake removal process? See pictures

[autographcollector11]

Do these pieces show possible signs of flake removal? If so, how was it done and is this what they call a core? I may have posted this way back when but these are much better pictures. There are 2 different items.
Or-is this all natural flaking due to freeze thaw?

[autographcollector11]

One more picture if the second one....

[kayakaddict]

It does to me and I knap a little but knowing the context would be nice.  Sometimes even a piece of driveway gravel can look interesting.  Are you sure of the material?  just thinking outloud here.  I see something, those ridges...

[sneakygroundbuzzard]

well its hard to tell on those pieces
but, the ridges look evenly spaced enough to have been done intentionally by taking flakes
but i see no signs of even small bulbs where the flakes would have originated
even pressure flaking leaves a small bulb
i wouldnt call them cores
flake cores usually have a shape like an octagon,nonagon or decagon etc
and usually have the top side some what concaved to make removing a blade easier
i agree that sometimes even driveway gravel looks like it may have been knapped
i find lots of it in lumberyard lots, when i deliver building supplies, that at first glance look like it may have been knapped
but when i pick it up and looks at it more i can tell it was either done by nature or machinery from the mining process