The shape of artifacts and structures can be very important in determining not only what they are (obviously) but also when they were likely to have been made.
Jennie Brower and I found this harpoon head (along with a number of other artifacts) while excavating the burial that first indicated that the site was not just a recent settlement. The shape of this harpoon head, with the pinched “waist” is one that was found at the earliest sites from the Inuit expansion into the eastern Arctic. When I saw it, I realized we were not excavating a late precontact burial.
Out of Ice and Time 