Wednesday I made an an inspection of a prehistoric quarry site here in Washington, a site that has long been known to archaeologists. There are several of these quarries, and all of them are just ravines where the thick layer of glacial cobbles that underlies much of the city is exposed on the surface. Where there was so much stone, people were not inspired to be very careful with the resource, so the process was very messy. They started by picking up cobbles, or digging them out of the slope, and then knocking off a few pieces to see what was inside. Many were rejected at that stage, like the ones shown above. Others were worked down into rough bifaces we call turtlebacks. Most of those turtlebacks were transported elsewhere to be made into tools, but many were unsatisfactory for some reason and those were left at the quarry. In making them these ancient Indians were, again, not very careful, so the process had a particularly high ration of waste flakes to finished project, leaving the whole area buried in broken pieces of stone like the ones below.