DRF,
Those looks like chert to me. I have several pieces I have picked up in the Bighorn Basin area in Wyoming while hunting that appear to have been scrapers.

The area is littered with chert rocks laying on the ground everywhere. Many the size of a big, baked potato and about the same shape. Sometimes they are fractured in have or smaller.

But the scrapper pieces definitely look more intentional.

My wife and I have put hundreds of hours in fields metal detecting but never found an arrowhead. Congrats on your finds.