Orthoceras is a marine cephalopods that date back 400-600 million years ago. The name Orthoceras means “straight horn,” and refers to its long conical shell. These specimen have been polished and ready to be displayed.
The average size of these Orthoceras: (The Length is what mostly varies)
X-Small – 1 to 1.5 inches (Long)
Small – 1.5 to 2.0 inches (Long)
Medium – 2.0 to 2.5 inches (Long)
Large – 2.5 to 3.0 inches (Long)