Pleistocene Papers at the Rochester Meetings. 219 
terminal moraines, or often formed during the glacial recession 
while no halt or re-advance of the receding ice-margin permitted 
the formation of moraines. But the irregular distribution and 
grouping of the drumlins, their absence upon man}' large areas 
thickly covered by drift, and the occasional occurrence of lone 
drumlins, remain to be explained and seem to present the most 
difficult problem relating to the action of the ice-sheet. 
In discussion, Prof. R. D. Salisbury thought the accumula- 
tion of drumlins easy to understand, but could not account for 
their occurrence in limited belts and groups or singly, while ad- 
joining large tracts liave none. The term englacial drift he would 
restrict to the drift carried long distances in the upper part of the 
ice without intermingling with the more plentiful drift in the basal 
part of the ice-sheet. Much of the drift transportation he be- 
lieves to have taken place by dragging under the ice. 
The extra-morainic drift of the Susquehanna valley. By Gr. 
Frederick Wright. The extreme advance of the ice-sheet is 
held to be marked in the Susquehanna region by a thin mantle of 
drift with plentiful bowlders, extending to a distance of several 
miles in front of the conspicuous belt of hilly drift denominated 
the terminal moraine. In tracing the moraine through Pennsyl- 
vania, the author, with the late Prof. Henry Carvill Lewis, named 
this extra-morainic drift a "fringe," believing its deposition to 
have been nearly contemporaneous with the accumulation of the 
morainic hills. Terraces of stratified drift deposits, with infre- 
quent bowlders, occurring farther south along the Susquehanna, 
which have been regarded by McGee as evidence of a marine 
submergence changing the valley to an estuary, are thought in- 
stead to be of fluvial origin, belonging to a time when the land 
there was slightly depressed, but not to the sea level, near the 
close of the Glacial period. 
In discussion, Mr. W J McGee defended his interpretation of 
the terraces; and Prof . R. D. Salisbury objected to the term 
"fringe," because this extra-morainic drift is referred by him, as 
also by McGee and others, to an earlier epoch of glaciation, ap- 
parently several times as long ago as the last glacial epoch when 
the moraine was formed. 
SECTION E, AMERICAN ASSOCIATION. 
Terminal moraines ht Neiv England. By C. H. HlTCHCOOK. 
