240 PROCEEDINGS OF THE ACADEMY OF [1888, 



{Macrocheilus) brevis White, described in the supplement to voL 

 III, of the Expl. and Surv. west of the 100 merid. synonymous 

 with M. ventricosus Hall. 



Macrocheilus newberryi Stevens. 



Loxonema newberryi Stevens, 1858. Am. Jour. Sci,, (2), vol. XXV,. 

 p. 259. 



Macrocheilus newberryi Hall, 1858. Geol. Iowa., vol. I, p. 719. 



The specimens collected at Des Moines present considerable 

 variation : some are typical M. neivberryi, from which others gradate 

 into forms more nearly approaching that described by Hall from 

 Alpine Dam as 31. fusiformis ; hence their identity is not improbable. 

 This is also in corroboration with the suggestion of Dr. White in the 

 Indiana geological report for 1883 that " with full collections at 

 hand, it will be difficult to clearly define the specific characters 

 between M. newberryi, 31. planus and 31. fusiformis." 



Orthonema conica Meek and Worthen. 



Orihonema conica Meek and Worthen, 1866. Proc. Acad. Nat. 



Sci. Phila., p. 270. 

 Orthonema conica Meek and Worthen, 1873. Geology 111., vol. 



V, p. 390. 

 This species is represented by only two specimens, both somewhat 

 smaller than those figured by Meek and Worthen. 



Actaeonia minuta Stevens. 



Loxonema minvta Stevens, 1858. Am. Jour. Sci., (2), vol. XXV, 



p. 260. 

 Actoeonia minuta Meek and Worthen, 1873. Geol. 111., vol. V, p. 



594. 

 This is one of the most abundant of the small gasteropods occur- 

 ring in the bituminous shales overlying coal No. 3. 



Aclisina minuta Stevens. 



Aclis minuta Stevens, 1858. Am. Jour. Sci., (2), vol. XXV, p. 

 259. 



Common ; associated with A. robusta, compared with which it is 

 much more slender, and the spire possesses three or four more 

 volutions. 



Aclisina robusta Stevens. 



Aclis robusta Stevens, 1858. Am. Jour. Sci., (2), vol. XXV, p. 

 259. 



