EDITORIAL 405 



to open up the problems widely. The atmospheric and cli- 

 matic factors will receive special attention, as will also the 

 reciprocal development of land and sea periods, the conditions 

 of expansional, restrictional, and provincial life evolution, and the 

 special functions of base-leveling, sea-shelves, epicontinental seas 

 and atmospheric changes in controlling life progress. 



The course in glaciology will embrace a discussion of the 

 physics of glaciers, their chronological development, the dis- 

 tinctive phenomena of glacial deposits, and their interpretation. 



The two courses will run parallel. They are only offered 

 for the coming summer. 



Besides these, the usual courses in physiography, meteorology, 

 general and structural geology and field work will be offered by 

 Professor Salisbury, assisted by Messrs. Goode, Atwood, Cal- 

 houn, and Finch. 



ERRATUM 



On p. 225 of the current volume, for " The glacier on Mount Iztaccia- 

 huatl is advancing" read : the glacier on Mount Iztacciahuatl is retreating at 

 the rate of about two meters a year. H. F. R. 



