Elem Flake Tools Flake Scrapers (55)Flake scrapers are various shaped flakes that exhibit use wear and/or secondary flaking on one side. All but two of these were of Borax Lake obsidian, one was basalt and one was Napa obsidian. The Napa obsidian scraper (0-105) had two hydration bands; one with a mean of 1.2 microns, indicating recent edge breakage ~200 B.P. However, most of the artifact had a mean of 11.7 microns, indicating manufacture ~21,000 B.P. This is likely the oldest stone tool recovered during the project.Flake Knives (4)Flake knives are usually more than casual flakes picked up and used. These flakes often show intentional thinning or sharpening along one or more edges to create a more precise cutting or scraping edge. All flake knives were of Borax Lake obsidian.Special Flake Tools (6)Casual flakes can be used as drills, engravers, and spoke-shaves (for shaving the bark off basketry sticks or arrow shafts). The materials collected had 4 examples of gravers, one spoke-shave, and one drill. All were of Borax Lake obsidian.Flake Blades (6)Flake blades are un-retouched flakes with a length more than twice their width. For most chipped stone tools, the longer and thinner the initial flake of stone, the better and sharper the finished tool. The shape of that initial flake is dictated by the shape of the core of rock from which it is obtained and the method by which it is removed from that core. During the manufacturing process, a core can be casually hit on any flat surface (platform) to remove usable flakes of stone. However, to obtain the longest and thinnest flakes, the core must be prepared and shaped to allow their removal. This process requires extensive knowledge and experience in stone tool manufacture. The resulting flakes are long, straight, and very thin. In sorting through the randomly collected chipped stone, 5 Borax Lake obsidian and one basalt flake blade were found. Flake ToolsFlake tools are chipped stone flakes that were casually used for cutting, scraping, drilling or engraving with little or no secondary shaping or sharpening. Most flake tools have no distinct shape other than a straight or pointed cutting edge. Due to this lack of distinct shape, few were purposefully picked up or plotted by the Tribal monitors during the monitoring process. Most of the flake tools recorded at the lab were from bags of random obsidian flakes that were collected. There were 72 flake tools recovered during project monitoring.All obsidian chipped stone tools that appeared to have diagnostic shapes were submitted for hydration analysis. Hydration readings were converted to approximate years B.P. (Before Present) using Thomas Origer’s (1993) rate for Napa obsidian and the Borax Lake/ Napa obsidian conversion factor developed by Kim Tremaine and Dave Fredrickson (1988).