150 years ago: "Common sense tells us that the primitive people who made haches and tools were able to make figures..."

Licking County, Ohio, bird figure stone

1) this object is an undisputable artifact

2) this object has a consensus (generally agreeable) likeness to a bird

3) this object combines skilled flint working with skilled artistic interpretation of the bird form

4) this object was found in the local context of pre-historic stone tools
5) this object was found in the local context of other flint bird likenesses

One may conclude this object is a figure stone.

"Common sense tells us that the primitive people who made haches and tools were able to make figures... ...As to the Symbols and Figures, although I have gathered of these some types which may be seen at my house to-day, numbering about fifty analogous shapes on which the human work is evident, I have converted very few people, and of the number, not one Englishman. Why-they say to me-are you the only one who finds Figure Stones ? Have they never been found anywhere else than at Abbeville ?-and-mention one collection besides your own in which they have been seen ...To-day, Sir, your examples will be questioned, I do not say that I shall have gained my cause, but Truth will have made one more step, and will strike forcibly by coming from two sides."

    - From a lettter from Jacques Boucher de Perthes to Victor Chatel, Oct 20th, 1866

Side 2 with scale. The bird figure has a serviceable and/or symbolic graver tool feature as the bird's beak. 

The thickness of the bird seen from above as it stands on its edge

Here is another flint and crystal bird figure with a graver tool as the bird's beak from Flint Ridge, Glenford, Ohio, featured in a post last October.

-kbj