skiffer

Etymology
Presumably.

Noun

 * 1)  Slate.
 * 2) * 2014, Charles Francis Hall, Narrative of the Second Arctic Expedition Made by Charles F. Hall, Cambridge University Press (ISBN 9781108071468), page 582:
 * The occurrence of this common Utica slate species so far north is interesting, and, taken with its appearance in the Trinuclid Skiffer of Sweden (Linnarsson, loc. cit, p. 70, fig. 27), where it is also of the same small size as here, gives it a wide
 * 1) * 2014, Charles Francis Hall, Narrative of the Second Arctic Expedition Made by Charles F. Hall, Cambridge University Press (ISBN 9781108071468), page 582:
 * The occurrence of this common Utica slate species so far north is interesting, and, taken with its appearance in the Trinuclid Skiffer of Sweden (Linnarsson, loc. cit, p. 70, fig. 27), where it is also of the same small size as here, gives it a wide
 * The occurrence of this common Utica slate species so far north is interesting, and, taken with its appearance in the Trinuclid Skiffer of Sweden (Linnarsson, loc. cit, p. 70, fig. 27), where it is also of the same small size as here, gives it a wide

Etymology
.

Noun

 * 1)  slate