126 B. SHIMEK AFTOKIAN POSSILIPEROUS GRAVEL AND SAND BEDS 



7. A yellow loess, liglit both iu color aud texture, probably post-Wisconsin, 

 found only near the Missouri Valley, and blending more or less with (6). 



6. A yellow, rather heavy loess, probably post-Iowan, blending with (7) and 

 sharply separated from (5). 



5. A bluish gray, compact post-Kansan loess, very variable in thickness. 



4. The Loveland — a iieavy joint clay, usually reddish, evidently belonging to 

 the melting period of the Kansan, reaching at least 40 feet in thickness. 



3. The Kansan drift, very variable in thickness. 



2. The Aftonian gravel, sand, and silt, up to 40 feet in thickness. 



1. The Nebraskan drift (pre-Kansan), which varies up to at least 40 feet in 

 thickness, but the greater part of this buried under other deposits. 



The total thiclmess of 5, 6, and 7 does not exceed 35 feet on the west 

 side of the Missouri and rarely reaches 90 feet on the Iowa side. 



DETAILED DESCRIPTION OF F08S1LIFER0US SECTIONS 



Order of treatment. — For convenience the sections are taken up in geo- 

 graphical order and are numbered consecutively, the general order being 

 from north to south. 



1. Akron section. — This was made in sinking a well on the Severin 

 Jensen farm, in the northwest quarter of section 33, township 93 north, 

 range xlviii west, about 2 miles east of Akron, Iowa. 



The well is located on a gentle slope of one of the swells or ridges by 

 which the typical rolling Kansan of this region gradually drops down to 

 the valley of Beaver Creek a half mile north. The Kansan is here covered 

 with loess, w^hich is more or less fossiliferous, as at the quarter-section 

 corner on the north line of section 32 and in the cellar of the Searles 

 house mentioned below. 



Mr. Jensen reports his well as 24 feet deep and reaching down to a 

 "hard-pan" (probably Kebraskan drift). A somewhat deeper boring 

 brought up "little pieces of slate" (probably Cretaceous shale). 



Eesting on this hard-pan are 7 or 8 feet of sand and gravel. At a depth 

 of about 20 feet a bed of very ferruginous sand was encountered, and in 

 this were found the bones and teeth of Mammut mirificum,. 



Above the sand and gravel (Aftonian) there is a bed of hard clay 

 mixed with a little sand and gravel. A part of this was dark in color. 

 This is evidently Kansan drift with Loveland joint clay. 



The topmost layer is a softer yellow clay, evidently loess. 



The owner had made several attempts to sink wells within a few rods 

 of the present well. In one of these he found stratified water-bearing 

 sand at a depth of 12 feet. In another near by he reached a *^'black hard- 

 pan" (evidently Nebraskan), with a little sand and gravel (seemingly 

 Aftonian) resting on it. 



