678 FRANK S. MILLS 



ice, by a larger and more powerful south-flowing stream which 

 had the potential of terrace-carving, either by diminished load or 

 diminution of volume — possibly both. The accident of position 

 and preservation is entirely independent of the presence of pro- 

 jecting spurs. 



It is believed that an application of Davis's theories of ter- 

 race origin, pattern, and preservation, and their adaptation or 

 non-adaptation to a given problem, may often afford suggestions 

 as to the history of valley development by streams. 



Frank S. Mills. 

 Andover, Mass. 



