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Webster 1913 Edition
Ammonite
Am′mon-ite
,Noun.
[L. cornu
Ammonis
born of Ammon; L. Ammon
, Gr. [GREEK] an appellation of Jupiter, as represented with the horns of a ram. It was originally the name of an. Egyptian god, Amun
.] (Paleon.)
A fossil cephalopod shell related to the nautilus. There are many genera and species, and all are extinct, the typical forms having existed only in the Mesozoic age, when they were exceedingly numerous. They differ from the nautili in having the margins of the septa very much lobed or plaited, and the siphuncle dorsal. Also called
serpent stone
, snake stone
, and cornu Ammonis
. Webster 1828 Edition
Ammonite
AM'MONITE
, n.[Cornu ammonis, from Jupiter Ammon, whose statues were represented with ram's horns.]Serpent-stone, or cornu ammonis, a fossil shell, curved into a spiral, like a ram's horn; of various sizes, from the smallest grains to three feet in diameter. This fossil is found in stratums of limestone and clay, and in argillaceous iron ore. It is smooth or ridged; the ridges strait, crooked or undulated.