Finally got around to knapping some mystery chert I found under a trussel bridge in north central alabama. I dont think it was native, it had been quarried somewhere and hauled in and dumped to support the bridge. most was fractured really bad but I got a few good spalls that I brought home, heat treated and knapped. really slick, really tough and really sharp. Some of the highest quality chert I have ever put my hands on... wish I knew what is "was".