As yoots we used to find shells like this in the woods along tall creek embankments. Those fossils were calcified and crumbled in the hand. This one is a little less brittle. Made by Sampson Mordan of England. Material is sterling and it works as a mechanical pencil. Mechanism deploys telescopically. Circa 1880. Closed length without larger ring 2 1/2 inches. Extended 3 3/4 inches.