Arkose. Term used by Brongniart for granular [Quartzite], which see.
Chiastolite-slate scarcely differs from clay-slate, but includes numerous crystals of Chiastolite; in considerable thickness in Cumberland. Chiastolite occurs in long slender rhomboidal crystals. For composition, see Table, [p. 377.]
Chlorite-schist. A green slaty rock, in which chlorite, a green scaly mineral, is abundant. See [p. 465.]
Clay-slate, or Argillaceous-schist. See [p. 465.]
Eurite and Euritic Porphyry. A base of compact felspar, with grains of laminar felspar, and often mica and other minerals disseminated (Brongniart). M. D'Aubuisson regards eurite as an extremely fine-grained granite, in which felspar predominates, the whole forming an apparently homogeneous rock. Eurite has been already mentioned as a plutonic rock, but occurs also in beds subordinate to gneiss or mica-slate.
Gneiss. A stratified or laminated rock, same composition as granite. See [p. 464.]
[Hornblende Rock], or Amphibolite. Composed of hornblende and felspar. The same composition as hornblende-schist, stratified, but not fissile. See [p. 376.]
Hornblende-schist, or Slate. Composed chiefly of hornblende, with occasionally some felspar. See [p. 464.]
Hornblendic or Syenitic-Gneiss. Composed of felspar, quartz, and hornblende.
Hypogene Limestone. See [p. 465.]