This is the base of a broken biface from a Pre-Dorset site. I'm holding it right side up in the photo - the broken tip would have refit on the top of the biface. It most likely functioned as an harpoon endblade or lance head. I find it interesting for the very high side notches. The part of the base below the side notches is usually only a few millimetres tall, but on this one its almost 2 cm.
The same base in situ next to a flake
This is a similar high notched endblade from another site a couple hundred metres away. This one was found point down sticking out of the ground.