624 J SARLEN BRETZ 



with abundant root and rootlet casts throughout and with reddened 

 upper surfaces of each deposit, aggregating 50 feet or more/ 



The mature topography is older than the scablands and the 

 basalt plain. Literally hundreds of isolated groups of maturely 

 eroded hills of loess stand in the scablands. Their gentle interior 

 slopes are identical with those far from the scabland tracts. But 

 their marginal slopes, descending to the scablands, commonly are 

 very steep, over large areas amounting to 30° and even 35° (Figs. 

 I, 2, and 3). These steep slopes are seldom even gullied, except 



Fig. I. — One of a group of loessial hills in the scablands a few miles southwest of 

 Rock Lake. One of the steepened slopes and its alignment are shown. Photo by 

 O. C. Clifford. 



where a drainage line leads out from the hill group to the scabland. 

 Where the minor valleys transected by the steep slopes lead back- 

 ward into the interior of a hill group they are simply hanging 

 valleys. 



There are few places where basalt occurs in these steepened 

 slopes. Where present, it is always restricted to the lower part and 

 shows itself in conspicuous ledges. 



A very striking and significant feature of the steepened slopes is 

 their convergence at the northern ends of the groups to form great 



I Near Harrington and near Kahlotus are two excellent cuts which show this very 

 well. 



