PAPERS ON GEOLOGY AND GEOGRAPHY 415 



Galha ohrussa exigaa (Lea). The fossils have deeper 

 sutures and more shouldered whorls than the recent 

 specimens. 



Galha elodes jolietensis (Baker). Four small speci- 

 mens appear referable to jolietensis, varying toward 

 elodes. 



Galha parva (Lea). Tlie marl specimens are rather 

 smaller than individuals from the recent fauna, showing 

 variation toward a dalll-Yike form. 



Galha dalli (Baker). Typical. One specimen is larg- 

 er than an}' recent individual seen, measuring 5 mm. in 

 length. 



LAND GASTKOPODS 



Caryclihim exile H. C. Lea. Rare. 



Vallonia gracilicosta Eeinhard. Eare. 



Succinea retusa Lea. Common. 



Succinea avara vermeta Say. Rare. 



Sfrohilops affiuis (Pilsbry). Rare. 



Strohilops lahi/rinthica (Say). Rare. 



Pupoides marginatns (Say). Rare. 



Vertigo ovata Say. Not uncommon. 



Belicodiscus parallelus (Say). Rare. 



Pgramidula alternata (Say). Common. The color 

 markings are Avell preserved. 



Pyramidida solitaria (Say). Common. The color 

 bands are well preserved. 

 . Gastrodonta ligera (Say). Rare. 



Zonitoides minKScula (Binney). Rare. 



Zonitoides arhorea (Say). Rare. 



Circiuaria concava (Say). Not common. 



Polygyra hirsnta (Say). Common. 



Poly gy I a monodon (Rackett). Common. Some speci- 

 mens are more globose with a higher spire. 



Polygyra pennsylvanica (Green). Abundant. 



Polygyra clansa (Say). Abundant. 



Polygyra thyroides (Say). Not common. Fifty per- 

 cent of the specimens have a tooth on the parietal wall. 



Polygyra multiUneata (Say). Common. 



