8 
or less distinct in the divisions or chambers, agreeably to 
the nature of the stratum in which the specimens are found. 
The section figured is from a Bath specimen, and shows 
several varieties of compact earthy marie, dendritical, &c. 
and the divisions more or less perfect, or obliterated, as it 
was cut rather irregularly, and the double line of the siphun- 
culus is in some places very unintelligible ; it is, however, 
very conspicuous in many specimens just under the thin 
shell of the keel, and appears to be nearly continuous. 
Walcot’s figure (Bath Petrifactions, fig. 41, p. 32) appears 
a worn specimen, the inner whorls being destitute of trans- 
verse costae. Its foliated sutures are sometimes more distinct. 
i 
