A rock layer below the Marcellus Shale could prove to be another incredible source of natural gas.

The Marcellus Shale captured public attention when leasing and drilling activities began pumping billions of dollars into local economies and citizens began debating the environmental, social and economic impacts. All of this began suddenly in 2004 when Range Resources Corporation drilled the first Marcellus well using modern drilling technology.

Now, just a few years later, the Marcellus Shale is being developed into one of the world's largest natural gas fields. However, what we are seeing today from the Marcellus is only the first step in a sequence of natural gas plays. The second step is starting in the Utica Shale.

The Utica Shale is a rock unit located a few thousand feet below the Marcellus Shale. It also has the potential to become an enormous natural gas resource. The Utica Shale is thicker than the Marcellus, it is more geographically extensive and it has already proven its ability to support commercial production.

It is impossible to say at this time how large the Utica Shale resource might be because it has not been thoroughly evaluated and little public information is available about its organic content, the thickness of organic-rich intervals and how it will respond to horizontal drilling and hydraulic fracturing. However, the results of early testing indicate that the Utica Shale will be a very significant resource in addition to the Marcellus Shale.