It just looks like adze to me... Those grooves on the bottom look like they got there from scraping it across a hard surface to put the bit back on it when it got dull.
While I have them out I thought I would post my smallest shell adze.
No, they are bone awl sharpening grooves, but you would need to look at them with a loupe or microscope to see for certain, and I can't get that close of a shot. Definitely used as an adze and sharpening tool.
At a foot long and full grooved, this adz is probably about as heavy duty as they got. As usual for New England hardstone, the material is basalt: