The deepest part of this sea was located in the eastern part of the basin, so more sediment and organic matter was able to accumulate eastward. As a result, the Marcellus Shale today is thickest in the east and thins westward. Because of the quantity of organics in the shale, where the Marcellus Shale is thicker it is likely to contain a large amount of natural gas and be of the most interest for economical extraction.