TIJRRILITES 



the Chalk marl. Several species abound at Riiigmer in 

 in Sussex, and Mount St. Catherine near Rouen. 



In our plate we have g^iven a representation of part 

 of a specimen which shows the form of the outer lip ; we 

 were favoured with the use of this specimen by G. Man- 

 tel, Esq. of Lewes, 



