302 The American Geologist. May, 1892 
Heide in 1887 led me to the belief that the surface formation was 
not last glacial. But Dr. Wahnschaffe’s conclusion doubtless 
rests on much fuller data than my own. 
Nomenclature. The classification and nomenclature employed 
in mapping the drift of north Germany is so different from that 
to which the American geologists are accustomed, that both the 
maps and the accompanying descriptions are liable to misinterpre- 
tation unless one is familiar, in advance, with the exact meaning 
which is attached to each particular term. Many of the terms in 
use are the same as those employed in America, but the signifi- 
cance attached to some of them is altogether different. | In Amer- 
a most unfortunate name 
ica, for example, the term upper till 
—is generally understood to mean englacial or superglacial till. 
In Germany, the same term (oberer Geschiebemergel) has a very 
different signification, and to one not posted concerning the tech- 
nical meaning of the term, a most deceptive one. The term itself 
might suggest the till of the last glacial epoch as distinet from 
the till of greater age, but this is not its meaning, though no till 
is “upper” till (oberer Geschichbemergel) which is not of last glacial 
age. But not all of the till of the second glacial epoch is classed 
as “upper” till, 
A mantle of bowlder-bearing sand frequently covers the till of 
the last glacial epoch. The same sand sometimes rests upon the 
older drift. Whether this super-till mantle covers second glacial 
till, or whether it rests upon the earlier drift where the later failed 
to be deposited or preserved, it is known as ‘‘upper bowlder-bear- 
ing sand” (oberer Geschichbesand), or, briefly, as ‘‘upper sand” 
(oberer Sand). If IT understand correctly the meaning of the 
terms, the bed of till immediately beneath the ‘‘upper sand” is 
classed as ‘‘upper till” (oberer Geschiebemergel), if it be, or if it 
be believed to be, last glacial. The same bed or till, if not coy- 
ered by the mantle of ‘‘upper sand,” is likewise ‘‘upper till.” 
The ‘‘upper till” of any given locality is therefore the uppermost 
layer of second glacial till, which there exists. If there be sey- 
eral layers of second glacial till separated by beds of sand or 
gravel, as is often the case, only the uppermost. of these several 
beds is “upper till,” while all the other layers of second glacial 
till are grouped with all the layers there may be of first glacial 
till, as ‘‘lower till” (anterer Geschicbemergel. ) 
Just as the uppermost layer of second glacial till in any place 
