236 



The pen sketch plate No. 1 gives some idea of the appearance of 

 one of these benches (see pen sl^etch section 32, Washington Township). 

 Plate VI shows beyond the ti'ees a side view of one of the spur-lilve ex- 

 tensions of a bench occuiTing in section 4. Eloomington Township. (See 

 contour map No. III. wliich also shows position of the partly buried head- 

 land.) 



Xo. 1. Pen fcketeh of Attached Spurs and Benches. Section 32. Washington Township. 



Pofit-(jhicifil History. Since the close of the laking stage Bean Blossom 

 River has developed a meandering com'se on its broad floor. Only in 

 the narrowest sections of the valley has it succeeded in spreading its 

 meander belt across the entire floor. For the most part it keeps to the 

 west or south side of the valley, and yet still a>ssumes a meandering habit 

 for considerable stretches. In other Avords, the stream does not fit the 

 present dimensions of the broad valley, which accordingly must have been 

 brought about by other conditions than that resulting from lateral cutting, 

 by a mature stream. Ci-oss sections of the valley at its broadest places 

 reveal a slight curvature of surface in the center and occasional abandoned 

 meandering channels. This slight variation from a plain sui-faee suggests 

 flood plain construction. Whether this constructive work antedates the 

 glacial episode of Bean Blossom is not certain, but it would seem from 

 the data at hand, that the present iwst-glacial Bean Blossom has not had 

 time or the ability to do much constructive work since pleistocene time. 



Yoini(/ Tallrijs. Traversing the steepest slopes of Bean Blossom, are to 

 be found numerous V-shaped valleys, with remai'kably steep channels, 

 ending their lower course at the point of intersection of the valley floor 

 with the adjacent slope. In all cases small alluvial fans are built on the 

 valley floor witll their apex pi-ojecting but a few feet or yards at most 

 beyond the mouths of the young valleys. In none of the observed cases was 

 it found that the level of the valley floor would extend into the mouth of 

 the young valley. It is therefore believed that the greater part of the cut- 

 ting of these young valleys may date subsequent to the preglacial filling. 

 The fact that alluvial fans and not deltas with steep outer edges and 

 flat tops occur at their mouths, suggest that they have been constructed 

 since the laking of the valley, and hence are regarded post-glacial. 



