C H A 



[84] 



CHE 



CHA'MBEEED. (chamlre, Fr.) Divided 

 into compartments by septa: the 

 chambered shells have also been 

 called multilocular. The fossil 

 chambered shells are exceedingly 

 numerous, and afford proofs of not 

 only having performed the office of 

 ordinary shells, as a defence for the 

 oody of their inhabitants, but also, 

 of having been hydraulic instru- 

 ments of nice operation and delicate 

 adjustment, constructed to act in 

 subordination to those universal 

 and unchanging laws, which appear 

 to have ever regulated the move- 

 ments of fluids. The history of 

 chambered shells illustrates also 

 some of those phenomena of fossil 

 conchology, which relate to the 

 limitation of species to particular 

 geological formations; and affords 

 striking proofs of the curious fact, 

 that many genera, and even whole 

 families, have been called into 

 existence, and again totally anni- 

 hilated, at various and successive 

 periods, during the progress of the 

 construction of the crust of our 

 globe. Prof. BucUand. 



CHAMITE. The fossil shell of the 

 genus chama. The Hon. Mr. 

 Strangways, in his description of 

 the Geology of the environs of 

 St. Petersburg, says, " There occurs 

 a bed of yellowish-white sand con- 

 taining organic remains. These 

 are only one large species of chamtte, 

 in very good preservation, usually 

 of a brownish colour and retaining 

 the original polish of the shell. 

 The two beds immediately above 

 this consist also of a sandstone 

 containing chamites. The lowest 

 is usually of a reddish or even rosy 

 colour, and contains vast quantities 

 of chamites, or rather fragments of 

 them, strewed throughout its mass, 

 in the direction of the planes of 

 stratification. The upper bed is 

 ^ equally filled with chamites, some 

 of which have a tendency to 

 iridescence or metallic lustre. Cha- 



mites are found in the supracre- 

 taceous deposits, in the cretaceous 

 group, and in the oolite formation. 

 CHAEA. A genus of aquatic plants 

 found both recent and fossil. Fossil 

 chara3 occur in formations of differ- 

 ent eras. Charae are often of con- 

 siderable importance to the geologist 

 in characterizing entire groups of 

 strata. The seed-vessel of these 

 plants, says Sir C. Lyell, is re- 

 markably tough and hard, and 

 consists of a membranous nut 

 covered by an integument, both of 

 which are spirally striated or ribbed. 

 The integument is composed of five 

 spiral valves, of a quadrangular 

 form. The stems of charse are 

 found fossil in great abundance in 

 the Scotch marl or travertin, they 

 are striated, and while the striae of 



. the stems turn, like the worm of a 

 screw, from right to left, those of 

 the seed-vessel wind from left to 

 right. "When first these seed- 

 vessels were discovered, in a fossil 

 state, they were supposed to be the 

 shells of an unknown species of 

 mollusk, and a genus was formed 

 for their reception, and termed 

 gyrogonites, or twisted stones, a 

 name by which they are still often 

 designated. 



CHA'EACEJE. In the vegetable king- 

 dom, the fourth order of Thalogens, 

 comprising the chara, &c. 



CHARA HISPIDA. A species of the 

 genus chara, above described. The 



. stems of this species are longitudi- 

 nally striated, possessing at the same 

 time a disposition to spirality. In 

 this, and other, species of chara, 

 the living plant contains so large a 

 portion of carbonate of lime in its 

 structure, that when dried it effer- 

 vesces strongly with acids. 



CHATOYANT. | (Fr .Ilseditd'unobjet 



CHATOYANTE. j dont la couleur varie, 

 suivant la direction de la lumiere, 

 qui le frappe.) A term used to 

 signify that changeable play of 

 light observable in certain minerals, 



