Pyritized gastropod

Whereabouts

In 1960, during the summer after graduation from high school, I worked as an assistant to the geologist of Consolidation Coal Company in Library, Pennsylvania.  My boss, Jacque VonFeld, kindly gave this to me, to add to my collection of rocks, minerals, and fossils.  It was the first time that I had ever seen a fossil replaced by fools gold.

Age & Formation
Pennsylvanian?
QTVR