40 



ferior Oolite and their diflerent locality would have con- 

 firmed us in the idea, did not that species also occur in 

 the blue Clay Cliff beyond the Old Castle near Wey- 

 mouth ; they are also both found together in the opposite 

 Kingdom at a place called Vaches noires near Honfleur. 



Fig. 3. represents a small specimen from France, and 

 in Mr. G. B. Sowerby's work upon Genera is a figure of 

 the T. costata from near Weymouth, taken from one 

 of Miss Benett's specimens. 



There is an unfortunate circumstance attending the 

 Generic name Trigonia ; it has long been applied to a 

 genus of Plants, and still remains in Wildenow's Spec. 

 Plantarum, a circumstance that has been hitherto over- 

 looked, and the name has become so familiar to Con- 

 chologists that we are unwilling to change it ; otherwise 

 we should recommend Lyridon as a substitute from the 

 resemblance of the lines upon the teeth about the hinge 

 to the strings of a harp. 



