Fantastic early cast iron sign

Keystone shape (measurements in photos)

Market st. Philadelphia

Shannon & Co. makers of Derricks & Engines

This was probably a building marker sign

Why is a Derrick called a Derrick? A 17th century English hangman named Derrick led to a gallows being called a derrick. From there, a crane with a moveable arm came to be called a derrick because it resembled a gallows.

Early advertising sign