50 



A MANUAL OF AMERICAN LAND SHELLS. 



The following species have actually been fouud fossil in the Post- 



pleiocene deposits : 



Zonites arbor eus. 



fuliginosus. 



inornatus. 



intertextus. 



ligcrus. 



gidaris. 

 Macrocyclis concava. 

 Patula solitaria. 



alter nata. 

 perspectiva. 

 Helicodiscus lineatus. 

 Strohila lahyrinthica. 



Folygyra auriformis. 

 Btenotrcma stenotremum. 



Mrsutum. 



monodon. 



Triodopsis palUata. 

 obstrieta. 

 appressa. 

 inflecta. 

 Mesodon albolabris. 

 elevatus. 

 exoletus. 

 thyroides. 

 clausus. 

 profundus. 

 Pupa armifera. 

 contracta. 



Succinea obliqiia. 

 Helicina* orbiculata. 

 occulta. 



Of the above all are now living and are equally numerous, excepting 

 Helicina occulta, a species most abundant in Post pleiocene days, but 

 now almost extinct.t The other species of Helicina is now confined to 

 more southern limits. 



In addition to the above, the following species, now living in the In- 

 terior Province, probably had their origin in Post-pleiocene times, and 

 will, no doubt, be found fossil in the " bluffs" : 



Zonites friabilis. 



IcBvigatus. 



suppressus. 



indentatus. 



internus. 



minusculus. 



limatulus. 

 Polygyra Dorfeuilliana. 

 leporina. 



Mesodon multilineatus. 



Pennsylvanicm. 



Mitcliellianus. 



dentiferus. 



bucculentus. 



Sayii. 

 Triodopsis tridentata. 



fallax. 

 Pupa pentodon. 



'Though not Pulmonaia, these two species are strictly terrestrial in their habits, and 

 are here introduced from their value on the question of the permanence of the Post- 

 pleiocene species. One of them is almost extinct, the other more restricted in its 

 range at present. 



t See Vol. I, 183, 184 ; Bland and Binney, Ann. Lye. N. H. of N. Y., IX, 289, 



