106 ILLINOIS ACADEMY OF SCIENCE 



*TABLE OF ANALYSIS OF LOESS AND ADOBE SOIL 



SiO, 72.68 64.61 74.46 60.69 79.77 66.69 19.24 



AL0 3 12.03 10.64 12.26 7.95 9.95 14.16 3.26 



Fe,0 3 3.53 2.61 3.25 2.61 3.39 4.38 1.09 



Feb 96 .51 .12 .67 



Ti0 2 72 .40 .14 .52 .70 



P 2 5 23 .06 .09 .13 .29 .23 



NnO 06 .05 .02 .12 .09 Trace 



CaO 1.59 5.41 1.69 8.96 .67 2.49 38.94 



MgO 1.11 3.69 1.12 4.36 .26 1.28 2.75 



Na„0 1.68 1.35 1.43 1.17 1.08 .57 Trace 



K 2 6 2.13 2.06 1.83 1.08 2.05 1.21 Trace 



H 2 0* 2.50 2.05 2.70 1.14 2.55 4.94 1.67 



CO, 39 6.31 .49 9.63 .77 29.57 



S0 3 51 .11 .06 .12 .41 .53 



C (Organic) 09 .13 .12 .19 2.00 2.96 



*Contains H of organic matter in Nos. 1-4. 



1. Nos. 1 to 5: Leverett, Frank: The Illinois Glacial Lobe. Mon. XXXVIII, 

 U. S. Geo.. Survey, 1899, p. 164. 



Nos. 6 and 7: Clark, F. W. ; The Data of Geochemistry. Bui. No. 491, U. S. 

 Geol. Survey, p. 487. 



MODE OF ACCUMULATION OF THE LOESS 



Orton suggested that the loess or white clay of southwest 

 Ohio represented the fine materials brought up by earth worms 

 and other burrowing animals from the underlying till. That 

 the aggregate work of earth worms is considerable, no one will 

 doubt, but the inadequacy of such agents in the accumulation 

 of the loess will be readily seen in the places where the deposits 

 have a thickness of several feet. It is also shown in the fact 

 that in the same general region there is no perceptible differ- 

 ence in the thickness of the loess whether it is immediately un- 

 derlain by drift or by such beds as gravel, sand, soil or peat, 

 which contain no fine constituents resembling loess. The clear 

 zone of contact that in most places separates the loess from 

 the underlying bed shows that the disturbance produced by 

 earthworms and other burrowing animals are relatively un- 

 important as far as loess accumulation is concerned. The 

 indifference in the thickness of the loess to the character of the 

 bed that lies beneath it, as stated above, indicates that the 

 loess could not have been derived from the underlying deposit, 

 but that it was transported, and laid down above the ma- 

 terial upon which it rests. The homogeneous, well sorted 

 character of the loess is proof that it has been carried and 

 deposited either by wind or water, for no other geological 

 agent is capable of so thoroughly sorting the material it de- 

 posits. 



