What Is It?

[bengal]

I found this in calhoun county Michigan. It was on the edge of a ravine that wash's out into a marsh.

It weighs about 3.5 OZ. Measures approx. 3"X 2" by 1.5" thick.

I almost did not pick it as it had a man made look about it.

I know it is corral of some type?

I would relly like to know what this is and what I might use to clean out the recess's to see more detail.

The top and bottom are opposites in that one is concave and the other convex. any info is greatly appreciated! Bengal