Crater. The circular cavity at the summit of a volcano, from which the volcanic matter is ejected. Etym., crater, a great cup or bowl.
Cretaceous. Belonging to chalk. Etym., creta, chalk.
Crop Out. A miner's or mineral surveyor's term, to express the rising up or exposure at the surface of a stratum or series of strata.
Crust of the Earth. See "Earth's crust."
Crustaceous. Animals having a shelly coating or crust which they cast periodically. Crabs, shrimps, and lobsters are examples.
Cryptogamic. Asexual, flowerless, or Acotyledonous plants; a term applied to half the vegetable kingdom in contradistinction to Phænogamic, sexual, or flowering plants. It includes Fungi, Sea-weeds, Lichens, Mosses, Ferns, &c., which have no obvious flowers, and no cotyledons (seed-lobes) to their spores or seeds. Etym., κρυπτος, cruptos, concealed, and γαμος, gamos, marriage.
Crystals. Simple minerals are frequently found in regular forms, with facets like the drops of cut glass of chandeliers. Quartz being often met with in rocks in such forms, and beautifully transparent like ice, was called rock-crystal, κρυσταλλος, crystallos, being Greek for ice. Hence the regular forms of other minerals are called crystals, whether they be clear or opake.
Crystallized. A mineral which is found in regular forms or crystals is said to be crystallized.
Crystalline. The internal texture which regular crystals exhibit when broken, or a confused assemblage of ill-defined crystals. Loaf-sugar and statuary-marble have a crystalline texture. Sugar-candy and calcareous spar are crystallized.
Cupriferous. Copper-bearing. Etym., cuprum, copper, and fero, to bear.