Lansing Pleistocene Geology. — WincheU. 281 
in the loess, meaning here the upland loess, the lower half of a 
deposit ninety feet thick, near Loveland, on the Boyer river 
is "pehbly." 
Mr. H. F. Bain gives (Geol. Iowa, vol. 5, p. 276, 1896) 
important instances of the cotemporaneons deposition of north- 
ern till in the loess, with illustrations. This is in Woodbury 
county, bordering on the Missouri, north of Pottawattamie 
county. 
He remarks that, for the exposure near Riverside station, 
the explanation has been offered of a slipping of till and 
loess from higher levels down into a lower terrace of loess. 
At another point, however, he claims that, whatever the case 
at Riverside station, that explanation cannot apply. It is at 
a sand pit northeast of the Brugier bridge, and he gives a full 
page photographic illustration. This exposure is "about 150 
feet above the river, and the till is above any similar deposit 
known to occur in this vicinity. The exposure shows a bed of 
typical till consisting of a matrix of dark brown clay, in which 
are numerous boulders of Sioux quartzyte (one of these is 
pointed out by the hammer) and other northern rocks, with 
loess of the usual, character, both above and below. * * * 
Th.e presence of the till in the loess indicates the cotempor- 
aneous origin of the two deposits, and it seems clear that in 
this case the explanation offered for the Riverside exposure 
cannot suffice, even if in that it be deemed sufificient." 
Such descriptions could be multiplied. 
14. These features are usual in the drift-loess further 
north. They have been mentioned by Todd in his account of 
the moraines of southeastern South Dakota and their attendant 
deposits,* although in his descriptions professor Todd strives 
to sustain a distinction between the loess and all forms of drift. 
It is plain, however, that such distinction was difficult (see 
pages 80, 82, 84. 88 and 89, of Bulletin No. 158). The terms 
till, or pebbly till, pebbly clay, or simply drift, are sometimes 
applied by him under the force of a theoretical distinction 
where the term loess would also a])])ly: and in some cases, 
without a theoretical distinction, would be preferable, especial- 
ly in those exposures of pcbblv "till" which he ascribes to sub- 
aqueous dejiosition (jip. 65 and 66). According to Todd char- 
• Bulletin No. 15S, U. S. G. S.. 1.S99. 
