At Flint Ridge, ancient American Indians quarried flint from pits they laboriously dug by hand into the bedrock, and many of these pits are still visible along the park trails. Once the flint was exposed, it was struck with hammer stones to break it into large chunks, then pried out of the surrounding rock with wooden poles. Favorable pieces were carried off to be knapped, expertly chipped and worked into tools. Because struck flint breaks into chunks with edges as sharp as glass, a skilled flint worker, or knapper, could shape raw flint into precisely formed tools such as spear points, knives, scrapers, and drills. Ancient flint workers sometimes used fire to heat the flint, which made it easier to knap and also made its colors more vibrant.