Abstracts. 



The Relation between Ice-Lobes South from the Wisconsin Driftless Area. 

 By Frank Leverett, Denmark, Iowa. 



Instead of a coalescence of ice-lobes from the east and west sides 

 of the driftless area in the drift-covered district to the south there was 

 an invasion and withdrawal of one lobe (the western) before the other 

 reached its culmination. The eastern lobe encroached upon territory 

 previously glaciated by the western, depositing a distinct sheet of drift 

 and forming at its western limits a well-defined morainic ridge. There 

 appears to have been a period of considerable length between the with- 

 drawal of the western lobe and the culmination of the eastern. 



Subsequently, however, there was a readvance of the lobe on the 

 west into northeastern Iowa, and this readvance appears to have been 

 contemporaneous with the nearly complete occupancy of northwestern 

 Illinois by the eastern ice-lobe. It seems not improbable that the ice- 

 lobes were then, for a brief period, coalesced for a short distance about 

 the south border of the driftless area. Evidence of complete coales- 

 cence, however, is not decisive so far as yet discovered. 



These developments serve to throw light upon the cause for the 

 scarcity of lacustrine deposits in the driftless area. They show that 

 there was at most but a brief period in which the southward drainage 

 of the driftless area was completely obstructed by the ice-sheet. 



The Production of Coal in iSq-/.. By Edward W. Parker. Extract 

 from the i6th Annual Report of the U. S. Geological Survey, Part 

 IV., Mineral Resources of the United States. 

 This report, consisting of 224 pages, constitutes the first chapter of 

 Part IV. of the i6th annual report of the Director, the well-known vol- 

 ume of "Mineral Resources" having, by a recent act of Congress, been 

 made a part of the Directors' report. This chapter, with four others, 

 has been published and given to the public in advance of the complete 

 volume. As indicated by the title, the chapter is principally a statis- 

 tical compilation, giving in great detail the record of coal production 



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