230 



After incising the valley and widening it by meander cutting, Bean 

 Blossom Creek began to aggrade its channel and at the close of the pre- 

 giacial time had filled it nearly to the level it is today. The evidence in 

 favor of such'a conclusion is as follows: (1) At all points where the creek 

 was protected from the invasion of glacial debris by promontories, such 

 as Mt. Tabor and Ellet's hill, it still flows on the north side of its valley. 

 At all other places it was driven to the south side by glacial debris. 



(2) The greater part of the clay and silt occupying the valley floor is of 

 precisely the same kind as that covering the unglaciated highlands and 

 valley slopes. It is evident that this filling simply repi'esents the wash 

 and soil-creep from the slopes and iiplands on either side of the valley. 



(3) At the mouth of the creek where the glacier crossed the country only 

 a patchy film of sand associated with bowlders composed partly of crys- 

 talline rocks cover the underlying clays, silts, etc. 



This conclusion agrees with the folloMing statement of Prof. Marsters 

 concerning the preglacial filling of the valley: 



"Inasmuch as the greater part of the clay and silt occupying the valley 

 floor is precisely the same in kind as that covexnng the unglaciated uplands 

 and valley slopes, it is evident that this filling simply represents the wash 

 and soil-creep from the slopes and uplands on either side. Moreover, the 

 rate of filling was so far in excess of the ability of the stream to carry 

 off its load that the preglacial valley became clogged with the waste to 

 such a degree that the stream noAv occupying the valley floor is for much 

 of its course quite unable to spread its meanders over the entire width; 

 only at the narrowest sections does Bean Blossom succeed in occupying 

 the entire valley from slope to slope. 



"Inasmuch as the filling of Bean Blossom at its mouth and for some 

 little distance up stream is covered over by a patchy film of glacial sand 

 associated with bowlders, composed partly of crystalline rocks, the under- 

 lying clays, silts, etc.. antedate the glacial coating. ^Moreover, the occur- 

 rence of benches (to be associated with the glacial history) resting upon 

 the valley filling also point to the same conclusion, that the present filling 

 of the valley, less the benches and the glacial sands, etc.. near the mouth 

 of the valley, is preglacial." 



The valley fillings, less the glacial sand, are. therefore, mostly pi-c- 

 silacial. 



