2)51 



Glacial History oi^- Bean Blossom Creek. 



As has been previously stated Bean Blossom Creek was laked bs' the 

 ice-sheet which crossed its lower course. At the time of its lakins? there 

 were deposited in its valley the deltas together Avith the loose materials 

 that now cover the benches on either side.* 



Post-Glacial History of Bean Blossosi Creek. 



Since glacial time Beau Blossom has. been a diminutive, meandering 

 creek in a broad, fiat-floored valley, and throughout all postglacial time it 

 has persisted in keeping to the south or Avest side of its valley. Evidently 

 it does not fit its present valley. This fact suggests that the creek has not 

 been able, on account of its diminutive size and the lack of time, to do 

 much constructive work since the ice retreated. It is now at grade for 

 ten miles above its mouth and must be actually aggrading its channel. 



We quote Prof. Marsters for a more detailed description of this 

 topic.** 



"Since the close of the laking stage Bean Blossom River has developed 



a meandering course on its broad fioor. Onlv in the narrowest sections 



■ r 



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 assumes a meandering liabit for considerable 

 stretches. In other Avords, the stream does not flt the present dimensions 

 of the broad A'alley, Avhieh, accordingly, must have been brought about by 

 other conditions than that resulting from lateral cutting, by a mature 

 stream. Cross 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 surface suggests flood plain 

 construction. AVhether this constructive work antedates the glacial 

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

 at hand, that the jiresent postglacial Bean Blossom has not liad tinu' or 

 the ability to do much constructiA^e AA^ork since pleistocene time." 



Tavo more tilings of interest in connection with Bean Blossom Creek 

 remain to be explained. They are: (1) Tlie reason for the channel of the' 

 creek keeping to its south bank, and (2) the reason why the slopes on the 

 south side of tlie valley are steeper than those on the north. 



''See Marster.«, loe. cit. for further discussion of this subject. 

 •'■"'■'Loc. eit. p. 236. 



