Crossword clues for ammonoid
The Collaborative International Dictionary
ammonoid
ammonoid \ammonoid\ n. 1. one of the coiled chambered fossil shells of extinct mollusks; same as ammonite.
Syn: ammonite
Wiktionary
ammonoid
a. Characteristic of an ammonite n. ammonite
WordNet
ammonoid
n. one of the coiled chambered fossil shells of extinct mollusks [syn: ammonite]
Usage examples of "ammonoid".
Jurassic marine strata are often correlated worldwide with great precision and confidence by recognition of a regular succession of ammonoid fauna that occurs in the same sequence wherever marine sediments of suitable age are preserved.
Because they evolved rapidly, had worldwide distribution by virtue of their open-water habitats, and species are readily distinguished, ammonoids are index fossils for the Jurassic.