The Primary Sector (CH4)

When Philly was established the sector it would have fallen in was the primary sector. It was known for their development of products. "In 1960 the first paper mill established in North America was built upon the Wissahickon, near Germantown, by William Bradford."(http://www.ushistory.org/philadelphia/philadelphiafirsts.html) 

The dedication of its workers to help its city with the productions of goods actually allowed them to grow so much that at one point in history it was the largest city!