IOWA ACADEMY OF SCIENCES 79 



At Galva, 111., a black soil at the base of the loess is 

 well exposed in a clay pit at the brickyards east of the city. 

 A large log was found imbedded in ihis soil which here has a 

 depth of two feet. The overlying loess is fifteen feet in depth. 

 A well at the brickyards penetrated forty feet of till below the 

 buried soil, of which the upper thirty feet has a yellow color 

 and the remainder a blue-gray color. 



In south w^estern Carroll county. 111., there are extensive 

 exposures of a soil at the base of the loess, made by the 

 Chicago, Burlington & Northern Railway company, the loess 

 having been removed to make a fill across the valley of John- 

 son creek. Probably a half acre of the buried soil is here 

 exposed to view. It has a deep black color to a depth of ten 

 or twelve inches, beneath which it assumes a greenish-yellow 

 color, such as is presented by sub-soils beneath poorly drained 

 regions. This sub-soil is leached as far down as exposed, a 

 depth of three feet. This locality was visited last November 

 by Professors Calvin, Udden, Bain and myself, and each recog- 

 nized the clear indications of a long interval prior to the loess 

 deposition. It may be noted in this connection that Judge 

 James Shaw mentioned a soil in Carroll county in his report in 

 the Geology of Illinois which apparently has the same horizon 

 as the one just described. It was found at a depth of fifteen 

 feet and a deposit of wood two or three feet in thickness was 

 associated with it. (*) 



On the portion of the Illinoian sheet in southeastern Iowa 

 many excellent exposures of the Sangamon soil are found. An 

 exposure similar to that in Carroll county. 111., has been made 

 at West Poiot, Iowa, where the Chicago, Ft. Madison & Des 

 Moines Railway company has excavated to obtain filling for 

 its tracks. The loess has been removed over an area several 

 rods square, leaving the buried soil at the base of the excava- 

 tion. Although the exposure is on the crest of the ridge which 

 marks the western limits of the Illinoian drift, the soil is of a 

 deep black color and has a depth of several inches. This expos- 

 ure was visited by Professor Chamberlin, Mr. Bain and myself in 

 August, 1896, as were also several roadside exposures between 

 West Point and Denmark, and between Denmark and Ft. 

 Madison. 



Exposures in other portions of southeastern Iowa are given in 

 connection with the discussion of the Yarmouth weathered zone. 



(*) Geology of Illinois, Vol. V, p. 



