Editorial Coimiicnf. 193 
the lowan ice-epoch, and that would make it five times the 
period elapsed since the final retirement of the ice. Post-glacial 
time has been computed in various ways, and it has been pretty 
nearly unanimously agreed that post-glacial time does not ex- 
ceed 10,000 years, and probably amounts to aliout 8,000 year.^. 
Accepting the lower term, the age of the Lansing man is found 
to be near 40,000 years. These time-ratios, however, are 
tentative, as given by Chamberlin, and may require consid- 
erable modification. 
From a study of the interglacial gorge running throrigh 
the west part of the city of Minneapolis, the 'vriter calculated 
that about 15000 years were rsquired for its excavation I'y 
the Mississippi river.* It was supposed to have been fonr.cd 
immediately prior to the Wisconsin epoch and after the lowrui. 
(3n that supposition the close of the lowan epoch was approxi- 
mately 23,000 years ago. If 8,000 years be added to this for 
the duration of the lowan (which is probably too ^mall an al- 
lowance) the commencement of that epoch, which ma\' be as- 
sumed to be about cosval with the Lansing skeleton, was about 
31,000 years ago. If, however, the interglacial Mississippi 
gorge at Minneapolis was excavated at some earlier interglacial 
epoch, say the Buchanan (pre-Iowan) or the Aftonian (as 
suggested by Mr. Upham) it antedates the lowan loess, and 
cannot serve as a factor in any calculation as to the age of the 
Lansing skeleton. 
It will require, therefore, considera1)le further and careful 
examination of the loess shi^ets of Iowa, and of their relations 
to the till-sheets, as well as the marginal features nf the till- 
sheets themselves, to enable anyone to fix with an^' certainty 
the age of the Lansing skeleton more exactly than is above in- 
dicated. That it dates from glacial time, at some remote point 
in the complex history of that age, is about all that can be 
afiirmed from the present state of knowledge of the drift de- 
posits. 
It remains to call attention to a newspaper story which af- 
firms that formerly a cemetery of the Fort Leavenwortli pene- 
tentiary was located at or near this place, and that the skeleton 
is but one of numerous others that could probably be found in 
the immediate vicinity if sufficient exploration should be under- 
* An approximate interglacial chroncinieter, Am. Geol., vol. x, p. 69 and 
302, 1892. 
