167 
AMMONITES triplicate. 
' TAB. CCXCII. Sf TAB. CCXCIII .-Fig. 4. 
Spec. Chau. Discoid ; volutions exposed,, costa- 
ted ; costas large, equal to the spaces between 
them, each divided into three as it passes 
over the front ; aperture suborbicular. 
TPhXS Ammonite has five or six volutions, across the 
latter of which there are two or three rather oblique, 
deep, furrows, or contractions of the whorl, probably 
formed by a thickening of the lip at several periods of 
growth, an occurrence that is rather rare in the genus, 
and has even been adopted as a generic character.* 
The costse are nearly straight and equally elevated upon 
the sides ; they are very regularly divided into three 
narrow ribs, as they pass over the rounded front. The 
cast of tfip inside differs from the outside in being plain 
along the middle of the front. The diameter is nearly 
four times its greatest thickness. 
Sent me by Mr. Crawford, jurx. from near Malton, in 
Yorkshire, where he found it in the Pisolite formation. 
Tab. 293, fig. 4. represents a part of another specimen 
found by myself some years ago at Shotover, near Ox- 
ford, in a marly Limestone containing much sand, 
probably the Calciferous Grit, a stratum contiguous to 
the above. 
* See Montfort, p. 79, Genus Planulites; and p. 87, Ellipsolitesj also 
Mineral Conchology, tab. 32, Ellipsolkes funatus : and v. 2, p. 189 
Am. constrictus. The genus Ellipsolites must certainly be abolished, and 
its species ranged under Ammonites, the oval form being quite accidental. 
