PLEISTOCENE OF CAPITOL HILL 171 



1. Fill and altered drift, yellow, in places with a thin line 

 of calcareous nodules at the base. Two feet. 



■1. Drift, yellow, pebbly. Two feet. 



3. Silt, brownish, no fcssils. Two feet. 



4. Silt, red, no fossils. Two feet. 



5. Clay, buff, bearing both pebbles and fossils. Five feet. 



Laterally this gives way without a break to alternating 

 gray and buff loess, with many fossils and a few concre- 

 tions, which here is four feet thick. Below it is exposed 

 one foot of dark b'ue fossiliferous loess. At the contact 

 there were found several iron-coated limestone pebbles 

 two inches long. Two feet above the base of the buff 

 loess was found a chert pebble two inches long, and at 

 several points both the blue and buff loess show layers 

 and pockets of sand, about six inches thick and several 

 square feet in area. Pieces of wood are quite common in 

 loess of both colors. 



A few feet from the above section a mass of Carboniferous 

 shale was shown in the wall. It was twenty feet long by three 

 feet thick and was underlain by typical gray, pebbly Wiscon- 

 sin till while above it lay altered till which contained lime con- 

 cretions. 



While the great sand lens described in the second section is 

 overlain by loess on the south side of the cutting, on the north 

 side it lies directly beneath modified drift and loess which evi- 

 dently have been disturbed. It seems probable thai il represents 

 an immense sand bowlder which was forced into its present posi- 

 tion by the ice. The contorted character of some of the coarser 

 parts lends to bear out this theory. 



Aside from showing the presence of a young drift on the 

 loess these exposures reveal unusually well the work of 4 he 

 glacier at the extreme limit of its advance. The intermingling 

 of the drift and the loess with its fragile shells, many of which 

 are still entire; the variation of materials within small inter 



vals of space; and the preseni f a greal lens of sand lying 



on the body of loess — all these are features which show how- 

 gentle and yet how irresistible was the action of the ice. 



The staged of alteration of the Wisconsin drifl were well 

 shown in several localities. The second section described is 

 quite typical. The thinness of the drift in this general region 

 is to lie expected, but the fact that il changes from unaltered 



