Wisco?is{n Kettle Moraine. 205 



The Glacier du Bois, the terminal portion of the Mer de Grlace, 

 the Argentiere, and, less obviously, the Findelen, and others, so 

 far as their situation favored, have developed similar moraines, 

 and indicate that this is the usual method of deposit under these 

 conditions. Reference is here made only to the terminal deposit 

 of the ground 'f)ioraine^ eliminating, as it is quite possible to do, 

 for the most part, the material borne on the surface of the glacier. 



The Material of the Formation. — This topic, vsrhich is one of 

 primary importance in determining the origin of the deposit, 

 readily divides itself into three subordinate ones, all of which 

 need discriminative attention; (1) \ks.Q form of the constituents, (2) 

 their arrangement as deposited, and (3) their source. 



(1) Premising that the Kames, and those deposits which have 

 been associated with them in the literature of the subject, are 

 described as composed mainly of sand and gravel, it is to be 

 remarked, in distinction, that all the four forms of material com- 

 mon to drift, viz.: clay, sand, gravel, and boulders, enter largely 

 into the constitution of the Kettle range, in its typical develop- 

 riient. Of these, gravel is the most conspicaous element, exposed 

 to observation. This qualification is an important one in forming 

 an adequate conception of the true structure of the formation. 

 It is to be noticed that the belt, at many points, exhibits two dis- 

 tinct formations. The uppermost — hut not occupying the heights 

 of the range — consists almost wholly of sand and gravel, and 

 lies, like an irregular, undulating sheet, over portions of the true 

 original deposit. This superficial formation is confined mainly to 

 the slopes and flanks of the range, and to depressed areas between 

 its constituent ridges ; though, when the whole belt is low, it often 

 spreads extensively over it, so as sometimes to be quite deceptive. 

 But, where the range is developed in force, this superficial deposit 

 is so limited and interrupted, as to be quite insignificant, and not 

 at all misleading ; and, at some points, where it is more widely 

 developed, excavations reveal unequivocally its relationship to 

 the subjacent accumulations. In such cases, the lower formation 

 shows a more uneven surface than the upper one, indicating 

 that the effect of the latter is to mask the irregular contour of 

 the lower and main formation. ISTotwithstanding this, the upper 



