6 i 
but much deeper. The flat side and the want of longi- 
tudinal furrows shew that it is not I. Lamarckii of 
Parkinson, in the Geological Trans, v. V. p. 55. with 
which, according to his figure, Mr. Mantell has however 
confounded it. It agrees better with the description of 
Mantell’s I. Brongiarti, but not well with his figure of 
that species. 
In Chalk, not uncommon. 
The hinges here figured, serve well to illustrate the 
Generic characters. 
INOCERAMUS cordiformis. - 
TAB. CCCCXL. 
Spec. Char. Equalvalved, heartshaped, trans- 
versely and interruptedly waved ; beaks 
large, incurved ; anterior side angular. 
T he posterior side of this shell is not defined ; but 
rises gradually from a hollow beneath the incurved 
beaks ; the transverse waves are very high, and irregu- 
larly interrupted ; the width and depth are equal and but 
little exceeded by the length. The general form reminds 
us of Isocardia Cor, only that the hinge line being pro- 
duced, gives an angular form to the anterior side. 
The figure is taken from a remarkably fine specimen, 
filled with Flint, that was found at Gravesend. 
