Hammerstone.. You should see all the drilled items The Ais tribe made in my area. they are an extinct tribe. they drilled everything from sharks teeth, shell, stone and all lot of the pottery. I'm still not sure of the reason for drilling the pottery. some say it was to fix leaks. drilling a small hole in a cracked area and plugging it with hide or something to that affect. I don't go along with that because 90 percent of what I see are drilled near the rim. I thought at first it might be for suspension. like hanging multiple pots on a sturdy branch between 2 peoples shoulders for transport but they showed no signs of wear from that. maybe just weep holes to keep from overfilling. This particular site had several occupations from middle archaic 2 shortly after contact.