Answer:
gravity
Explanation:
Gravity from Latin gravitas meaning weight for gravitation is a natural phenomenon by which all things with mass or energy including planets stars or galaxies and even light are brought toward or gravitate toward one another gravity gives way to physical objects 
 
        
             
        
        
        
The Marcellus Shale also categorized as the Marcellus formation is a marine sedimentary rock unit of middle Devonian age found in eastern North America. It elongates throughout the major of the Appalachian Basin.  
The shale comprises huge unexploited reserves of natural gas, which makes it an attractive target for export and energy development. There are comparatively scarce presences of fossilized marine fauna found in the Marcellus, however, these fossils are still essential to paleontology.  
For example, the Marcellus comprises the primogenital known varied assemblage of thin-shelled mollusks, still possessing well-preserved shell microcomposition. It is also where goniatite, an extinct shelled swimmer identical to a squid, make their initial presence in the fossil record.