90 Kansas Academy of Science. 



receded the upper currents of the outer belt of the ice, upon 

 a width of probably ten miles, would pour down toward the 

 open land, causing the deposition of much subglacial till ; and 

 whenever a stratum of the englacial drift became covered with 

 new ice, it would probably be aggregated englacially or al- 

 together subglacially in drumlins. 



"And to conclude, drumlins are the effects of secular vicis- 

 situdes of climate on the border of the departing ice-sheet, 

 which seems to have owed its existence to the great altitude 

 of the land at the beginning of the glacial period. This glacier 

 seems to have been atended, when at its maximum extension 

 and volume, by depression of the land on which it lay, and to 

 have witnessed, during the retreat and removal of its load, a 

 progressive reelevation of the same area to its present height." 



Remarks on Drumlins. — Drumlins could not have been 

 formed by the tidal or river erosion of a once continuous slieot 

 of drift nor to the excavation and removal of the drift from 

 all intervening areas by the later glaciation mentioned, be- 

 cause, to accord with this view, the terminal moraine of the 

 later ice-sheet must vastly exceed their moderately observed 

 volume. (2) They are not the material of terminal moraines 

 swept over and massed in these peculiar forms by subsequent 

 farther advances of the ice-sheet, because neither the distribu- 

 tion nor the composition of drumlins seems to favor such an 

 hypothesis. (3) They were not made by superglacial streams, 

 charged with drift, pouring through crevasses or a moulin to 

 the land surface, there depositing their drift ; because there are 

 no signs of stratification, and because the distribution and com- 

 position oppose such a theory. (4) Drumlins are not anal- 

 ogous to the sand-bars of streams, because the areas bearing 

 them are not determined chiefly by the topography and rock 

 structure. (5) They do not seem to have been formed by 

 subglacial drift, leached out from the melting ice by surface- 

 melting and gathered from a large area of the ice surface and 

 concentrated on a smaller one by water action, thus to be 

 transformed into drumlins of true till, for the following rea- 

 sons: (a) The whole mass of the accumulated concentrated 

 surface drift must have been worked over bit by bit by the 

 ice before it could gain the structure of till. This would seem 

 to be a useless concentration, except as affording a possible 

 excessive supply of ready material for ice-dragging, (b) The 

 theory as a whole seems to be founded upon special interpre- 



