GLOSSARY. 



481 



DECIDUOUS, parts which are shed, as 

 leaves of trees. 



DELPHINULA, lat., delphinus, a dol- 

 phin ; a genus of shells. 



DELTA, alluvial deposits, formed by 

 rivers. 



DENDRITIC, branched, like a tree. 



DENTALIUM, lat., dens, a tooth; a 

 genus of shells. 



DENUDATION, the carrying away a 

 portion of overlying materials by 

 the action of water. 



DERMAL, belonging to the skin. 



DESICCATION, the act of drying. 



DETRITUS, disintegrated materials of 

 rocks. 



DICERAS, with two horns ; a genus 

 of shells. 



DICOTYLEDONOUS, a grand division of 

 the Vegetable kingdom, applied 

 to plants having two cotyledons, 

 or seed-lobes. 



DIDELPHYS, a marsupial animal, 

 allied to the opossum. 



DIKES, the intrusion of volcanic 

 among stratified rocks. The name 

 is derived from the term applied 

 in Scotland and the north of 

 England to walls, owing to these 

 ejections frequently presenting 

 the appearance of walls, in conse- 

 quence of the strata, on both sides 

 having been worn away. 



DILUVIUM, a term employed at an 

 early period of the science to de- 

 signate ancient alluvial deposits. 



DIP, the inclination of strata. 



DIPTERA, insects having two wings, 



DISCOIDAL, in the form of a disc. 



DISCORBITES, from lat., discus, a disc, 

 and orbis, an orb. 



DOLABELLA, lat., a little axe, or 

 hatchet ; a genus of shells. 



DOLIUM, a tun ; a genus of shells. 

 DOLOMITE, crystalline magnesian 

 limestone. 



DONAX, a wedge ; a genus of sheila. 



DRUSES, minute crystals, lining the 

 cavities of minerals; as, for ex- 

 ample, drusy quartz in the hollows 

 of flint nodules. 



E. 



EARTH'S CRUST, that portion of the 

 solid surface of the earth which is 

 accessible to human observation. 



EBURNA, lot., ebur, ivory ; a genus 

 of shells. 



ECHINODERMATA, hedgehog-skinned; 

 applied to creatures having a 

 prickly external integument, as 

 the echinus, or sea-urchin. 



ECHINUS, sea-urchin. 



no front teeth, as the Armadillo. 

 ELYTRA, wing-cases of insects. 

 EMARGINULA, lat., emarginatus, a 



notched margin ; a genus of 



shells. 

 ENCRINITE, a genus of lily-shaped 



animals. 

 ENTOMOSTRACEA, shelled crustaceans, 



as the Cyprides. 

 EOCENE, dawn of the recent or exist- 



ing period. 



EPHEMERON, the creature of a day. 

 ERODED, worn away. 

 ERYCINA, a surname of Yenus; a 



genus of shells. 



ESCARPMENT, the steep side of a hill. 

 ESTUARY, the mouth of a river alter- 



nately occupied by the waters of 



the river and the sea. 

 ETHERIA, one of the sea-nymphs ; a 



genus of shells. 

 EXUVIAE, organic remains. 



F. 



FALUN, a French term for the mid 

 die tertiary strata. 



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