202 Wisconsin Academy of Sciences, Arts, and Letters. 



traced. A portion of the paper will, therefore, relate to well as- 

 certained facts, while other portions will be in various degrees 

 hypothetical. If care is taken to distinguish between these por- 

 tions, no harm can arise from their association ; while the provis- 

 ional mapping will, it is hoped, prove of service in both stimu- 

 lating and guiding further investigation. The extent of the range 

 is likely to prove too great for the immediate time and means of 

 a single observer; while the broad and irregular, and sometimes 

 obscure, character of the belt is such that it is likely to be over- 

 looked, as a continuous range, as experience has shown, unless at- 

 tention be called to it, or the observer be keenly alive to distinc- 

 tions in drift topography. It is believed, therefore, that the pre- 

 sentation of some things that are only probable, not certain, will 

 not be without value. • 



It will be advisable to consider first, somewhat critically, the char- 

 acter of the formation. The following description, which is based 

 upon careful observation, relates more specifically to the moraine 

 iu "Wisconsin, where it is usually well developed, and may require 

 some modification in its application to the range where sub-aque- 

 ous deposits overlap or encroach upon it, and in other special sit- 

 uations. 



Surface Features. — The superficial aspect of the formation is 

 that of an irregular, intricate series of drift ridges and hills 

 of rapidly, but often very gracefully, undulating contour, consist- 

 ing of rounded domes, conical peaks, winding and, occasionally, 

 geniculated ridges, short, sharp spurs, mounds, knolls and hum- 

 mocks, promiscuously arranged, accompanied by corresponding 

 depressions, that are even more striking in character. These 

 depressions, which, to casual observation, constitute the most pe- 

 culiar and obtrusive feature of the ran^e, and o-ive rise to its de- 

 scripiive name in Wisconsin, are variously known as " Potash. 

 kettles," " Pot holes," " Pots and kettles," " Sinks," etc. Those 

 that have most arrested popular attention are circular in outline 

 and symmetrical in form, not unlike the homely utensils that 

 have given them names. But it is important to observe that 

 the most of these depressions are not so symmetrical as to merit 

 the application of these terms. Occasionally, they approach the 



