802 THE GEOGRAPHICAL SIGNIFICANCE OF FLOODS, 



layers in glaciers. This, by some observers, has been adduced as 

 evidence of the incompetence of ice-erosion. Yet this is what 

 one would expect from a study of ordinary streams. Ever}^ river 

 has a down-stream motion; nevertheless, at almost every point, 

 eddies are set up by reason of channel obstacles; and these 

 eddies give rise to breaking and .shearing of water-masses. 

 Compare also the breaking of waves, the wave of translation, the 

 undertow, the leaping of torrent flood-waters, and the violent 

 dashino- of the same around rocks and other channel obstructions. 

 Notwithstanding this evidence of waste force, no engineer of 

 repute would believe that such eddying and overthrusting of 

 water-masses argued corrasive incompetence for that particular 

 stream. On the contrary, these shearings reveal intense action 

 which finds partial relief upwards by reflection. Dr. W. G. 

 Woolnough, of Sydney University, in conversation with the 

 writer, mentioned the action of a great flood witnessed by him 

 in Fiji. So great was the rush of storm-water that, not only 

 water-masses, but large stones were thrown high above the 

 stream-surface by the tremendous force of the eddying current. 



Gannett's "Lake Chelan "(13) apparently marks the commence- 

 ment of a new era in glacial work. Fresh light is thrown on the 

 problem by his descriptions and discussion. 



Penck again, in 1899, as quoted by Davis,(9,a,p.319) stated the 

 case for vigorous glacial erosion in the Alps. 



Both Gannett and Penck have drawn attention to certain 

 similarities existing between glacial and ordinary stream-channels. 



It was, however, a comprehensive paper by Davis, in 1900,(3,a) 

 which caused the Writer- to become a " glacialist." As a result 

 of meditation on the excessive simplicity of Davis's statement, 

 the idea was entertained that the existence of a former great 

 ice-flood would throw light on such apparent anomalies as present- 

 day glacial stagnation, moraine-overriding by ice-masses, the 

 peculiar appearance of drumlins, and other points. 



Gilbert's contribution, in 1899, (17, a) marks a decided progres- 

 sive move. To him we are indebted for the term " Hanging 



