Tks Angus, We'll take special note of the way you have phrased your input.....
PW can probably be found in almost any drainages all over TX....But the thing for our artifact hunting is: was the quality good enough to flake AND was better quality chert / flint in low supply that would force them to use PW ?
Thats a very historical "diggers handle" you have chosen for postings...
Many many years ago there was a very old veteran texas digger of that name ( sort of the George Washington of flint )
Last we heard of him he had given up digging in favor of hand sewing quilts that kept him in his rocking chair at the rest home ...