■ Malott: The ''American Bottoms^' Region 39 



termined by notin^r the position of the outwash deposits shown 

 on the geological map. The stream that came in from the 

 pre-glacial ''American Bottoms" valley was likewise filled, 

 and, while its lower course has been partially resurrected, 

 much of the old valley is still a sandy flat into which the 

 rain waters readily sink instead of flovfing over the surface. 

 The southwest edge of the ''American Bottoms" in section 26 

 is a flat surface of a portion of this outwash plain. The 

 sand of which it is largely made up is exposed in the south- 

 flowing stream and ravine-like tributaries near the line be- 

 tween sections 26 and 27. 



Just north of Park there is a broad glacial col. It seems 

 that the water from the ice came from the vv^est over this 

 col and was discharged to the southeast thru section 27, prob- 

 ably finding its way out toward Plummers Creek along the 

 route of the present Cliffy Creek. Proof of the eastward 

 discharge of water thru this col is found not only in the 

 direction of flow indicated by the cross-bedding of the water- 

 laid material, but also in the presence of silt terraces due 

 to the ponded condition of the northeast tributary of Ore 

 Creek, in the north half of section 22. These silt terraces 

 are at exactly the same elevation as the broad glacial col. 

 This small pre-glacial valley leading southwest was ponded 

 by the ice and glacial debris to the depth of the water flow^- 

 ing out at the col. The glacial sediment which eddied into 

 this flooded pre-glacial valley combined with the indigenous 

 material carried into it by the regional wash to fill the valley 

 with silt, the remains of which still reveal its glacial history. 

 It is quite probable that the strong discharge over this col 

 resulted in lowering the head of the outwash apron in the 

 vicinity of Park. 



The outwash material so eflfectually filled the low^er part 

 of the valley now occupied by the "American Bottoms" that 

 the waters which gathered into it have never transgressed 

 the barrier. The middle and upper part of the valley became 

 a lake with the lowest margin at an elevation of 675 feet 

 above sea level. The southwest rim was the broad outwash 

 plain gently rising to the west. This outwash plain abutted 

 against the abrupt ridge to the south. There are no indi- 

 cations that the w:ater of the lake ever overflowed the barrier 

 at any point. 



