Mr, J. Lycett on the genus Quenstedtia. 137 
aggregate of these characters, it must be admitted, fully justifies 
the separation of Quenstedtia from Psammobia; and it yet remains 
to be demonstrated that true Psammobie are found in any rocks 
older than the Tertiary system, none of the so-called Jurassic 
Psammobie having hitherto exhibited the characters of that genus 
free from ambiguity. 
