116 McGEE MEMORIAL MEETING 



ing, was followed by uplift and subaerial erosion. The post-Lafayette 

 uplift and erosion was succeeded by subsidence, which, although not 

 so great in amount as the preceding Lafayette subsidence, was like- 

 wise accompanied by differential crustal movement. Three phases 

 of the Columbia formation, the fluvial, interfluvial, and low-level, 

 were recognized. 



McGee's work on the Lafayette was preceded by Hilgard's on the 

 "Orange Sand" of Mississippi, and the concept underlying the treat- 

 ment by each author was to a considerable degree similar. Numerous 

 observations previous to his own had also been made on both fluvial 

 and coastal Pleistocene phenomena. Since McGee's publications on 

 the "Appomattox" or Lafayette and the Columbia formations ap- 

 peared, the late Tertiary and Pleistocene geology of the Coastal Plain 

 had been studied in every coastal state from New York to the Mexican 

 border and throughout the Mississippi Embayment. The investiga- 

 tions are still in progress and their end is not yet in sight. As might 

 have been expected, many of McGee's conclusions have already been 

 greatly changed and it is evident that still further modifications are 

 necessary, but notwithstanding these changes in interpretation the 

 value of his influence on the progress of these researches has been so 

 great that to overestimate it would be difficult. By calling attention 

 to the similarity of phenomena throughout the area of the Coastal 

 Plain, by his attempt to treat these phenomena in a comprehensive 

 and connected way, by his proposing a valuable working hypothesis, 

 and by his attempts to correlate the fluvial and coastal terraces of 

 the non-glaciated areas of the south with phenomena in the glaciated 

 areas of the north, he has greatly contributed to the advancement of 

 geologic research. 



McGee's efforts were not confined to elucidating the geologic his- 

 tory revealed by those formations mentioned, for he endeavored to 

 trace in the Coastal Plain all the different geologic formations or 

 their stratigraphic equivalents throughout their extent, to interpret 

 conditions of sedimentation, to ascertain the source of the sediments, 

 and to correlate the record of sedimentation with that of the degrada- 

 tion of adjacent land masses. By aid of the information procured 

 from these different lines of inquiry, he endeavored to reconstruct the 

 geologic history of the Coastal Plain region from the end of the long 



