578 



J. H. BRETZ GLACIAL DRAINAGE OX COLUMBIA PLATEAU 



commonly anastomosing channels and rock-basins eroded in basalt, and 

 containing meadows, swamps, and lakes (figures 3 and 4). The local 

 name refers to the absence of soil over much of these tracts, the basalt 

 outcropping in ledges and over considerable level areas. The "Scab- 



FiGURE 3. — Channeled "Scaliland" of Si)okane Age 

 This area is on the plateau near the head of Grand Coulee. 



FiGiuE 4. — ispohane Drainage Channels in MUI-lengtli of Moses Coulee 

 The narrow inner channel is of Wisconsin age. 



lands" are commonly elongated tracts, with their channels and rock 

 basins elongated in parallelism. Some of these channels are canyons 

 several hundred feet deep. Almost all of the lakes of the plateau lie in 

 the Scablands (figure 5). Xone occur in the Palouse Hills. 



