142 B. SHIMEK PLEISTOCENE OF SIOUX FAJLLS AND VICINITY 



The second cut is connected with the first and lies east of it. A por- 

 tion of it is shown in plate 10, figure 1. On the northeast side it pre- 

 sents the following members : 



c. Sandy 3'ellow stratum, possibly ^eolian, 4 to 5 feet. 



h. Gray, weathered Kansan ( ?), 4 to 6 feet. 



a. Gravel, sand, and silt, the latter predominating : 



Sand, gravel, and silt, 2 feet. 



Dark fossiliferous silt, about 6 feet. 



Gravel and boulders, stratum ferruginous, irregular. 

 Weathered drift, probably Kansan, exposed at base. 



Three molars of Equus scotti were collected at the base of the fossilifr 

 erous silt, and fragments of bones were scattered through it. Near the 

 east end mollusk shells are very abundant and the following were col- 

 lected : 



*Planorhis hicarinatus Say. 

 *Planor'bis parvus Say. 



Planor^'is dilatatus Gld. 



Ancylus rivularis Say. 

 *Valvata tricarinata Say. 



Amnicola 



Segmentina armigera (Say) 

 H. and A. Ad. 

 *Physa Integra Hald. 



Physa sayi ( ?). 



Lymnwa reflexa Say. 

 *Lymncea caperata Say. 



Lymnwa JiumiJis Say(?). 

 ■^Pisicliiim compressum Prime. 



Pisidiinn ahditioii Hall (?). 

 *Sphcrrii(ni !^ulcatuni Lam. 



Anoclonta, probably .1. imhecillis Say. 

 *VaUonia costata Sterki, 1 specimen. 



The last species only is terrestrial. 



The species marked with an asterisk were reported in Todd's paper 

 (1899), Physa Integra appearing under the name Physa heterostropha. 

 This fauna is identical with that of the Aftonian. 



In the first cut this silt is replaced by sand, gravel, and boulders. 



14. Hamilton sand pit. — This pit is located south of the Illinois Cen- 

 tral cut on the east side of the same ridge. It presents the following 

 section : 



Heavy ferruginous, bluish joint clay, evidently Kansan, T feet. 

 Cross-bedded sand and fine gravel, 10 feet exposed. 



Mr. Hamilton reports that the sand stratum is about 25 feet deep. He 

 states that when digging a well near by he penetrated into a hard dark- 

 blue clay, possibly Nebraskan. 



15. Collins sand pii^.— This is located near the third cut from the west 

 along the Illinois Central Eailway, opposite the Hamilton pit. The sec- 

 tjon is as follows ; 



