THE CONTINENTAL GLACIERS OF THE "ICE AGE'! 309 



since these only attract attention. In 1893, when the finding of 

 the Oregon stone drew attention to these denizens of the drift, 

 the writer prophesied that other stones would occasionally be dis- 

 covered under essentially the same conditions, and such discoveries 

 are certain to continue in the future. 



Tabulated comparison of the glaciated and nonglaciated re- 

 gions. It will now be profitable to sum up in parallel columns 

 the contrasted peculiarities of the glaciated and the unglaciated 

 regions. 



UNGLACIATED REGION GLACIATED REGION 



TOPOGRAPHY 



The topography is destructional ; The topography is constructional; 



the remnants of a plain are found at the remnants of a plain are found 



the highest levels or upon the hill at the lowest levels in lakes and 



tops ; hills are carved out of a high swamps ; hills are molded above a 



plain ; unstable erosion remnants are plain in characteristic forms ; no 



characteristic. unstable erosion remnants, but only 



rounded shoulders of rock. 



DRAINAGE 



The area is completely drained, The area includes undrained 

 and the drainage network is arbores- areas, lakes and swamps, and 

 tent. . the drainage system is haphazard. 



ROCK MANTLE 



The exposed rock is decomposed No decomposed or disintegrated 

 and disintegrated to a considerable rock is "in place," but only hard, 

 depth ; it is all of local derivation fresh surface ; loose rock material 

 and hence of few types homogene- is all foreign and of many sizes and 

 ous; the fragments are angular; types heterogeneous; rock bowl- 

 soils are leached and hence do not ders and pebbles are faceted and 

 contain carbonates. polished as well as striated, usually 



in several directions upon each 

 facet ; soils are rock flour the 

 grist of the glacial mill. 



ROCK SURFACE 



Rock surface is rough and irreg- Rock surf ace is planed or grooved, 

 ular. and polished. Shows glacial striae. 



Unassorted and assorted drift. The drift is of two distinct 

 types; namely, that deposited directly by the glacier, which is 



