PLEISTOCENE MOLLUSC A FROM ILLINOIS 57 



Alaska, and the Whiteside County specimen adds another varia- 

 tion. Not enough material is at hand to ascertain whether this 

 variation is anything more than local. Modesta (under the name 

 of Pupilla blandi) is a common loess fossil in Iowa. In Illinois 

 it has been reported from the Yarmouth stage (Baker, 19206, 

 p. 271), and from deposits in the driftless area (Baker, igiob, p. 353). 



Pupilla muscorum (Linn.). Two specimens from the loess of 

 Whiteside County, apparently typical. 



Gastrocopta armifera (Say). Common in loess of Whiteside 

 County, and quite typical. 



Gastrocopta tappaniana (C. B. Adams). Abundant in the peat 

 deposit of Carroll County. 



Strohilops virgo (Pilsbry). Two specimens of this small land 

 shell occurred in the peat deposit in Carroll County. They are 

 typical. 



Sphyradium edentulum alticola (Ingersoll). A single specimen 

 of this small species occurred in the calcareous loess in Boone 

 County, collected by Mr. B. B. Cox. This species is reported 

 from but two other places in Illinois. These are as follows (data 

 from Baker, 1920&) : Aftonian, well boring near Rock Island, 

 cited as Pupa alticola (p. 240) ; Peorian or Wabash loess, near 

 Galena (p. 353). Its small size has probably caused it to be over- 

 looked in the examination of loess deposits from Illinois. 



Helicodiscus parallelus (Say). Common in yellow sand of 

 Wabash age near Ridott, Stephenson County. All of the speci- 

 mens are typical. 



Pyramidula shimekii (Pilsbry). This characteristic land mol- 

 lusk was found in two localities, both of Peorian age, loess of 

 Whiteside County and sands of Carroll County. But one speci- 

 men was collected in each place. Pyramidula shimekii is an 

 abundant fossil in the loess of Iowa and may be said to be char- 

 acteristic of the lowan or Peorian loess. No authentic records are 

 known from strata later than the Peorian. While it is common 

 in Iowa, it is rare in IlHnois, and records are known from but 

 one locality other than those listed (Galena in the driftless area, 

 Trowbridge and Shaw, "Galena Folio). It may have been listed 

 elsewhere under the name of Pyramidula cronkhitei anthonyi, which 



