I'm getting a bit confused here, there is only one piece of Bone/Tusk, correct?
At the narrow end where the square hole is, if you look where the narrow end is cut off, the end grain seems to show the dentine as a different pattern as seen in the picture below.
While doing a bit of a search for like tools, I came across a picture of very similar Inuit items. All of the descriptions of these were identified as petrified tusk. I should have saved the photos, but I didn't. Maybe an image search for Inuit ice axe will provide the picture again.
https://walrusivory.org/wp-content/u...py-980x784.jpg