THREE GLACIAL TILLS AT AMES, IOWA. 
JOHN E. SMITH 
The observations from which these data were obtained were 
made in an excavation opened for the basement of Wesley Foun- 
dation building just south of the athletic field of Iowa State Col- 
lege on Lincoln Way. 
The uppermost deposit which is found everywhere on the up- 
land in the vicinity of Ames, is the Wisconsin till, most of which 
at this place had been removed by erosion prior to the beginning 
of the work. A zone of red soil about two feet thick just beneath 
this till serves as an unmistakable indicator of the plane of sep- 
aration between it and the Kansan till below. 
The Kansan till varies from five feet to twenty feet in thickness 
which is about its regular variation in this vicinity. It is red at the 
top and varies through brown to yellowish below. The upper 
four feet of it does not effervesce in hydrochloric acid but the re- 
mainder of it is calcareous, though most of it shows the color of 
partly oxidized material. 
Beneath the Kansan till, which covers a rough, eroded surface, 
is a firm, compact, blue clay containing pebbles, cobbles, bowlders 
and fragments some of which bear glacial striations. The mate- 
rials of this till are all sizes and shapes and comprise many kinds 
of rock not found in the bedrock here, also fragments of wood, 
well preserved, and of coal. Many of the rocks of the till are un- 
Fig, 1. 1, Wisconsin till; 2 , Loess; 3, Kansan till; 4, Nebraskan till. The loess 
is not exposed in this pit. The contact between numbers 3 and 4 in the diagram is 
drawn to scale. Length of section, 40 feet. 
