352 NATURAL HISTORY BULLETIN. 



from 5, so that a lower talus has been formed, which extends 

 to the south to meet the base of the ridge a, but which is cut 

 off from it by the little stream. A part of this talus is shown 

 in fig. 2, PI. X, to the right, and its position at the base of the 

 north bluff will be made clearer by reference to d, PI. VIII, 

 and fig., I, PI. XL If at any time the talus <^had been pushed 

 across the narrow creek-bed to the ridge «, the waters of the 

 little streamlet would have formed a pond. If this had occurred 

 when the talus at the base of a reached only to the dotted line 

 at r, the horizontal distribution of the thin silt layer which 

 has created so much comment, would be exactly accounted for. 

 This damming of the tributary, and the subsequent slipping of 

 the talus might have occurred very recently, and even at low 

 water in the Missouri river. 



With the exception of this thin silt-layer, the Lansing 

 deposit seems to be a talus, and hence of but little value in 

 determining the age of the human remains. It certainly is 

 not loess, unless under that term we are to include practically 

 all the pleistocene deposits consisting of more or less inco- 

 herent materials. 



LOESS AND THE IOWAN DRIFT. 



It has been customary in very recent years to associate the 

 greater part of the loess with the Iowan drift, and because of 

 the alleged correlation, in some of the discussions of the Lans- 

 ing man the loess was employed as a measure of the age of 

 the human remains. In a previous paper* the writer attempted 



*Am. Geol. , vol. xxxii, pp. 362—4, Dec, 1903; also this Bulletin, pp. 

 337-40. 



