368 
Geology of Sydney. 
Centrum (Gr. kentron , the point round which a circle is 
described by a pair of compasses). The central portion 
or “body” of a vertebra. 
Cephalic (Gr. kephale , head). Belonging to the head. 
Cephalopoda (Gr. kephale ; and podes , feet). A class of 
the Mollusca, comprising the Cuttle-fishes and their 
allies, in which there is a series of arms ranged round 
the head. 
Ceratodus (Gr. keras , a horn ; odous , a tooth). A genus of 
Dipnous fishes. 
Cheirotherium (Gr. cheir, a hand ; therion, a beast). The 
generic name applied originally to the hand-shaped 
foot-prints of Labyrinthodonts. 
Chert. Differing from flint in being a rather less pure 
form of silica and having a flatter fracture. 
Clastic (Gr. Mast OS) broken). Fragmentary, non-crystalline. 
Coleoptera (Gr. koleos , a sheath ; pteron, wing). The 
order of Insects (Beetles) in which the anterior pair of 
wings are hardened, and serve as protective cases for 
the posterior pair of membranous wings. 
Condyle (Gr. kondulos, a knuckle). The surface by which 
one bone articulates with another. Applied especially 
to the articular surface or surfaces by which the skull 
articulates with the vertebral column. 
Conglomerate. Cemented and hardened gravel. 
Conifer 38 (Lat conus, a cone ; fero, I bear). The order of 
the Firs, Pines, and their allies, in which the fruit is 
generally a “cone.” 
Contorted (Lat. contovqueo, I twist together). Applied 
to rocks deformed by pressure. 
