638 PROCEEDINGS OF THE BALTIMORE MEETING 



Then was read 



WEATHERING AND EROSION AS TIME MEASURES 

 BY FKANK LEVERETT 



[Abstract] 



The paper set forth the use that may be made of weathering and erosion 

 in determining relative age of the several drift sheets. It also dealt with the 

 most important qualifying conditions that affect estimates. 



At the close of the reading of this paper, at 12.30 o'clock, adjourn- 

 ment was taken, discussion being postponed to the afternoon. 



The Society convened again at 2 o'clock, President Calvin presiding, 

 and took up the discussion of Mr Leverett's paper, the participants being 

 A. Penck, S. Calvin, F. Leverett, G. F. Wright, and G. K. Gilbert. 



The next two papers were then read : 



GLACIAL PHENOMENA OF SOUTHEASTERN WISCONSIN 

 BY WILLIAM C. ALDEN 1 



[Abstract] 



A graphic presentation by a map 9 by 10 feet, scale 1 mile per inch, of a 

 detailed study of the deposits of the Green Bay and Lake Michigan glaciers and 

 associated phenomena of late Wisconsin glaciation of southeastern Wisconsin. 

 The map represents an area approximately 8,600 square miles, which has been 

 studied by the author under the direction of Dr T. C. Chamberlin during 

 the greater part of the last ten years. The presentation comprised such de- 

 scription as the time permitted of the conditions affecting the advance of the 

 two glaciers, their relations to each other, the character, distribution, and mode 

 of formation of the several deposits, terminal and recessional moraines, out- 

 wash deposits, ground moraines, drumlins and eskers, the lithological composi- 

 tion of the drift and its significance. Evidence was presented by a deposit of 

 red till of a later readvance of the two glaciers southward to the vicinities of 

 Milwaukee and Fond du Lac. The shorelines and deposits of lake Chicago and 

 succeeding glacial lakes were also shown. 



CRITERIA FOR DISCRIMINATION OF THE AGE OF GLACIAL DRIFT SHEETS AS 

 MODIFIED BY TOPOGRAPHIC SITUATION AND DRAINAGE RELATIONS 



BY WILLIAM C ALDE]Sr 1 



[Abstract] 



The discussion was confined to phases illustrated by the pre-Wisconsin drift 

 of southern Wisconsin and northern Illinois. 



Introduced by T. C. Chamberlin. 



