Name/Title
AmmoniteEntry/Object ID
78.57.119Description
Crystal System: Hexagonal System
Description: Phylum: Mollusca
Class Cephalopoda
Sub-Class: Ammoniodea
Common Name: Ammonite
Age: Jurassic
Location: Upper Lias-Befrons zone, Whitby, Yorkshire, England
Description:One group of two ammonites in slate concretion. Tightly coiled, single valved shells with ridges.
Physical Characteristics:
Ammonites /'æm?na?ts/ are an extinct group of marine invertebrate animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs are more closely related to living coleoids (i.e. octopuses, squid, and cuttlefish) than they are to shelled nautiloids such as the living Nautilus species.
Ammonites are excellent index fossils, and it is often possible to link the rock layer in which they are found to specific geological time periods. Their fossil shells usually take the form of planispirals, although there were some helically-spiraled and non-spiraled forms (known as heteromorphs).
The name ammonite, from which the scientific term is derived, was inspired by the spiral shape of their fossilized shells, which somewhat resemble tightly coiled rams' horns. Pliny the Elder (d. 79 AD. near Pompeii) called fossils of these animals ammonis cornua ("horns of Ammon") because the Egyptian god Ammon (Amun) was typically depicted wearing ram's horns.[1] Often the name of an ammonite genus ends in -ceras, which is Greek (???a?) for "horn".
Fracture: Conchoidal
Grain Size: Fine
Hardness: 3 Calcite
Kingdom: Animalia (Animals)
Luster: Vitreous
Class: Cephalopoda
Phylum: Mollusca
Rock Origin: Terrestrial
Rock Type: Sedimentary
Streak: white
Subfamily: AmmonioideaCollection
Fossil CollectionAcquisition
Accession
78.57Source or Donor
Delmar Smith Fossil CollectionAcquisition Method
DonationLocation
Location
Container
CenterDrawer
Top ShelfShelf
RightCabinet
Case # 2Wall
WestRoom
Fossil RoomBuilding
Crater Rock MuseumCategory
Permanent
