Pleistocene Papers at the Madison Meetings. 167 
fined across the greater part of northern New Jersey and in- 
cludes the Pattenburg and High Bridge till deposits, which 
the author a year ago thought more probably referable to 
landslides. Though most of this drift is from the local forma- 
tions, some of the rock fragments came considerable distances 
from the north. The moraine and drift farther north denote 
more powerful ice action than on the area of the drift fringe. 
The divisions of the Glacial period shown by the diverse drift 
deposits seem to be properly called episodes in a single epoch, 
which was short in contrast with former geologic epochs, 
though its duration in thousands of years cannot yet be ap- 
proximately estimated. 
In discussion of the foregoing papers, Prof. T. C. Chamber- 
lin differed from the authors in his belief that the extra- 
morainic drift should be referred to a far earlier time than the 
moraine and more northern drift, as indicated by their con- 
trasts in extent of oxidation find erosion. The early high 
terraces, and the late low terraces, of the Delaware valley also 
are held to be decisive evidence of a very long interval be- 
tween the times of deposition of the drift on opposite sides 
of the moraine. 
Mr. Wauken Upham spoke of his observations of eskers ex- 
tending three to six miles south of the outermost moraine on 
Long Island, showing that the ice-sheet extended, probably 
during only a short time, considerably south of the moraine. 
He advocated the use of the terms marginal and re- 
treatal moraines, although at their times of formation each 
was at the receding termination of the ice. The fully oxi- 
dized condition of the extra-morainic drift was referred to its 
derivation chiefly from preglacial residual clays and alluvium 
and from weathering rock cliil's and knobs, like those of the 
Wisconsin driftless area and of the country south of the drift ; 
while the very uneven topography and fresh character of the 
moraines and drift farther north were ascribed to steeper 
frontal slope and more vigorous currents of the ice-sheet during 
its recession. 
Mr. Frank Levbrett stated that in the Mississippi basin 
much stream erosion took place between the times of the older 
and newer drift, requiring that interval to be several times 
longer than the postglacial epoch. 
