Definition of Marcellus shale in English:

Marcellus shale

(also Marcellus Shale)

noun

Geology
  • A highly bituminous black shale of Devonian age found in the north-eastern United States.

Origin

Mid 19th century. From Marcellus, the name of a town in New York State + shale.

Pronunciation

Marcellus shale

/mɑːˌsɛləs ˈʃeɪl/