31. The resulting elevated levels of carbon burial would account for the black shale deposition in the ocean basins. 32. The Marmontains Formation can be correlated with the Valzeina Formation of Graub�nden and black shales in the Engadine. 33. The formation of the foreland basin through rapid subsidence initiated a transgressive sequences that deposited basinal black shales . 34. In May 1943, as one of the shafts was being deepened, the miners encountered bands of soft, black shale . 35. Generally, black shale receives its influx of carbon from algae, which decays and forms an ooze known as sapropel. 36. A trio of teen-agers excavated it from the black shale of an abandoned New Jersey quarry 39 years ago. 37. The Ellsworth is composed of a lower part of interbedded brownish-black shale and an upper part of greenish-gray shale. 38. In order for a shale to be a black shale , it must contain more than one percent organic carbon. 39. In the upper part, intercalations of black shale with gypsum flakes and abundant pyritic micritical concretions appear, some with ammonites. 40. The serpentine rock at the head of the Eel River is crushed to a green clay or shining black shales .
