56 McGEE MEMORIAL MEETING 



as expert in charge of Soil Water investigations. This position he 

 held until his death. 



McGee made many valuable contributions to geography. In the 

 Great Basin work he investigated the cause of the peculiar curvature 

 of lateral moraines issuing from gorges into broad valley bottoms; 

 some conditions of erosion by glacial ice, especially in the develop- 

 ment of cirques, rock basins and U shaped canyons; and the law of 

 foothill development in that region. In his study of northeastern 

 Iowa he ascertained the conditions under which certain drift features 

 were developed, and set forth a method of determining direction of 

 the ice flow without depending on evidence of glacial striae. In this 

 work also he set forth a law of land profiles applied in the driftless 

 area, and a law of varigradation in the stream gradients. In his 

 work on the Atlantic Coastal Plain McGee added many notable ideas 

 to our growing science of Geomorphy, then in its infancy. He showed 

 that geologic history could be read from topographic forms, and this 

 means was extensively used by him and by myself in unraveling the 

 Coastal Plain geology. Another important mode of recognizing the 

 formations was developed at the same time and that was by homo- 

 geny, or correlation by identity of genesis. This criterion was very 

 essential where fossils were lacking. One very important phase of 

 this work was in the differentiation of terrace deposits and correla- 

 tion of terraces which represented the same stage in the topographic 

 development of a region. It was by this means that I mapped many 

 areas of Lafayette and earlier Columbia deposits as well as non-fossil- 

 iferous outliers of underlying Tertiary and Cretaceous deposits. 



Some of these lines of work led McGee to develop a classification of 

 geographic forms by genesis which was set forth in a paper published 

 in the first number of the National Geographic Magazine. McGee's 

 observations in lower California on his trips to Seriland and Tiburon 

 Island afforded some very instructive facts regarding erosion conditions 

 in arid lands. He found that sheet flood erosion was an important 

 factor in levelling the surface and producing peneplains at various ele- 

 vations above the sea. This idea has proven to be a very valuable 

 one, and has greatly simplified our conception of the topographic de- 

 velopment of certain regions. 



The paper entitled "Outlines of Hydrology" which McGee pre- 



