THE NAUTILUS. 



63 



that the pink loess, believed to be of Sangamon age, is the rich- 

 est in number of syecies, and that the characteristic post-Iowan 

 (Peoriari) fossil, Pyramidula shimekii occurs only in the buff 

 loess. Whether this distribution is to be considered as apply- 

 ing to the whole body of the loesses of this area, or is simply 

 the result of local collecting, cannot be known until more ex- 

 tensive collections are made. The collections made by Dr. 

 Leighton are from several localities in both Madison and St. 

 Clair counties and also from different levels in the deposits, and 

 these are believed to represent fairly well the general distribu- 

 tion of the loess faunas of this region. It is probable that a 

 larger number of the minute species could be found as a result 

 of prolonged search carried on especially for them. The mater- 

 ial has been placed in the University of Illinois Museum through 

 the courtesy of the Illinois Geological Survey. They are num- 

 bered P 738 to P 764 of the collection of Palaeontology. 



TABLE OF DISTRIBUTION OF 

 Concretionary horizon. 

 (Above underlying till, be- 

 lieved to be Kansan.) 



Yarmouth interval. 

 Pink loess believed to be of 

 Sangamon age. 



Upper part of loess. 



Buff loess. 



Early Peorian interval. 



LIFE IN LOESSES NEAR ALTON. 

 Polygyra prqfunda pleistocenica. 

 Castoroides ohioensis (incisor 



tooth). 

 Mammut americanum (Kerr). 



(Reported by Worthen.) 



Polygyra prof undo, pleistocenica. 

 Polygyra multilineata altonensis. 

 Polygyra hirsuta. 

 Polygyra appressa. 

 Pyramidula alternata. 

 Helicodiscus paralellus. 

 Gastrocopta armifera. 

 Zonitoides arborea. 

 Circinaria concava. 

 Succinea ovalis. 

 Helicina occulta. 



Pyramidula shimekii. 

 Succinea ovalis. 



