The Lcess and its Fossils. 



211 



Nothing derinite can be said concerning the distribution of 

 the species of which only the generic names have been given 



(/. e. Phvsa sp ? and Pisidinvi sp ?) but species of 



these genera closely related to the fossils, and in all proba- 

 bility identical with then:., are widely distributed throughout 

 the eastern portion of the United States. 



The most marked feature of this fauna is the mingling of 

 forms now belonging to northern and middle latitudes.' 



Of the species named, Jive are boreal (or high-altitude) ; ten 

 extend over both the Northern and Interior Regions (but not 

 beyond); eleven have a very wide distribution over all of the 

 eastern part of the United States; and^rc are now restricted 

 to the Interior Region. 



Judging from the sets of fossils upon which these notes are 

 based, the species herein mentioned, if arranged according to 

 their abundance and extent of distribution in the Lress, would 

 stand about as follows: 



Siiccinea verilli. 

 Snccinea lineata. 

 Patula striatella. 

 Pn^a decora. 

 Pii^a alticola. 

 Pupa muscoruni. 

 Z oil lies fiilviis. 

 Zonites liniatulits. 

 Snccinea ohliqaa. 



Vallonia ■pulehella. 

 Helicina occulta. 

 Snccinea avara. 



Vertis,o ovata. 

 Ferussacia subcylindrica. 

 Mesodon imdtilineata. 

 Limncea caper at a. 

 Limncea humilis -purva. 



Zonites arborcus. 

 Zonites radiatulus. 

 Zonites minusctdns. 

 Carychiuni exiguum. 

 Pupa pentodon. 

 Vertio;o oroiddii. 

 Snccinea oval is. 



Physa f 



Planorbis parvus. 

 Pisidinni ? 



1 The Northern and Interior Regions of the Eastern Province of Binney, 

 see Vol. V. 



