Fossilized Walrus Ivory Bowhead Whale Amulet

This little bowhead whale is somewhat of a mystery to me. When I look at the surface of the carving with a loop, it has the sheen and soft undulating surface of a piece that has been in the water for a long enough period to wear away any knife marks or raised edges. The two "V" shaped lines for the blow hole are barely visible. It has a hole through the top for attachment to something. I think that it is older than the 19th C. It has the number, "L 1231", inked along the lower left side, either a museum or collection identification.  

L. 1 5/8"