The shale, whose formation dates back to millions of years, covers a long stretch on the Northeast to the Southwest shore. Consequently, the formation forms a crucial source of natural gas reservoirs. Thus natural gas extracted from these reservoirs would be used as a source of energy.Marcellus Shale, like other fossil fuel formations such as oil and coal, was essentially formed through decomposition of remains of plants and animals over a long spell of time. Natural gas could be formed through two processes which include the following:Thermogenic formation. This process refers to the formation of natural gas as a result of temperature and pressure changes in the Earth’s crust resulting in compression effects on the overlying debris.Consequently, Marcellus Shale formation was as a result of a thermogenic formation process. Thus, the shale is a geological formation that was formed as a result of the accumulation of sediments in the sea. Consequently, organic matter (such as the remains of plants and animals) was compressed at extremely high pressures for a long time. This process resulted in the formation of thermogenic methane. The organic particles decomposed were covered in mud and other sediments. Consequently, the debris exerted pressure on the underlying organic matter. This cycle was carried on for long spells of time amounting to millions of years. Thus, with time, more and more sediments and debris was piled on the organic matter beneath the materials. This, in turn, continued to exert increased pressure on the organic matter. As a result, the organic matter was compressed. Consequently, the compression resulting from the overlying debris broke down the organic matter. This process was also aided by the existence of extremely high temperatures beneath the Earth’s crust (Victor, and Jaffe 26). Since the crust’s temperature increase with depth, at shallow deposits with low temperatures, more oil was produced as opposed to natural gas.