By now, most Americans have heard about the game-changing amount of natural gas found within the Marcellus Shale of Pennsylvania. That shale holds the largest amount of proved shale gas reserves in the nation. Because of that, it made Pennsylvania the second-largest holder of natural gas reserves in the nation. However, what most Americans don't know is that Pennsylvania is saturated with energy potential above and below the Marcellus Shale. That's important not just for American energy independence hopes, but for investors in companies like Range Resources (RRC -3.74%), EQT (EQT -2.72%), and CONSOL Energy (CNX -1.77%).

As the following slide from a recent Range Resources investor presentation shows, Pennsylvania has gas-bearing rocks above and below the Marcellus Shale in the Upper Devonian and Utica/Point Pleasant formations.

Source: Range Resources Investor Presentation (link opens a PDF).

Because of the stacked nature of the gas-baring rocks in the state, it actually helps to make much more of the state profitable for gas drilling. Companies like Range Resources, EQT, and CONSOL Energy can utilize multi-well pad drilling to save money, enabling each to drill on what might not have been economical acreage in the state.

To help investors gain a better understanding of the stacked nature of the state's gas bearing rocks I created the following slideshow. It shows the areas most saturated with natural gas as well as the positions Range Resources, EQT, and CONSOL Energy have in the play, companies that will be rewarding investors for many years to come.