362 The American Geologist. " ' "'"''• l908 - 
Wisconsin. It is believed thai loess of widely different ages 
urs in the Mississippi valley." Calvin (1. c. p. 118) says; 
"Loess, "i" a product resembling loess, was developed in con- 
nection with more than one drift sheet, and it is possible that 
the lowan loess blends into loess-like deposits of different age 
in some portions of the extra-marginal territory." 
There is at present no warrant whatever for the reference 
of all loess, and especially that of the Missouri river, to the 
lowan age. and even if it be possible to show that the Lansing 
skeletons rested in undisturbed loess this will not prove that 
they belong to the lowan. 
A thin layer of loess is found over a part of the lowan and 
the Wisconsin* and no connection has yet been established be- 
tween the lowan and the loess of the Missouri and Big Sioux 
river regions. Indeed, Bain refers to the northwestern loess in 
the following words :f 
"It is known, however, that loess in northwestern Iowa 
probably belongs to more than one geological epoch, and pro- 
fessor Macbride's observations in Humboldt county make it 
conclusive that the lowan did not cover the region immediately 
north of Carroll county as has heretofore been believed. The 
correlation of this loess in Carroll county with the lowan drift 
is accordingly open to considerable doubt." 
1 f these words apply to loess comparatively near to the 
lowan border, what shall be said of the great mass of loess 
along the Missouri and lower Mississippi rivers, covering an 
area vastly greater than the known lowan border region, and 
between which and the lowan no connection whatever has yet 
been established? 
It is the writer's opinion that the accumulation of a com- 
paratively large amount of loess along the border of the lowan 
drift is explained by the fact that this border follows the larger 
streams of this part of the state, the Iowa. Cedar, Wapsipini- 
con. Maquoketa and Turkey. The deposit is thickest in the 
southern portions of the area, where the river valleys are broad, 
and where winds could easily gather up quantities of dust from 
the sand and mud bars exposed at low water. In any case no 
siii-.nK. r... Proc. in. lead. 8ci., vol. iv. pp. 68-72, isms. Bain, n 
v.. in. Geol 8ur., vol. ix. p. 91, L899. Calvin, S., Bull. Geol. Soc. of 
Am., vol. x. p. 119, 1899; Iowa Geol. Sur., vol. xiii. pp. 328-9, 1903. 
i la. G( ol. sur.. vol . ix. p. 92, 1899. 
