TITLES AND ABSTRACTS OF PAPERS 151 



One section, under the ehainnansliip of I. C. White, gave consideration 

 to the following papers : 



CLIFT ISLAyDS JN THE CORAL SEAS 

 BY W. M. DAVIS 



{Abstract) 



The Marquesas Islaiuls, Tiitiiila, in Samoa, and Tahiti, in the Society group, 

 are all of volcanic origin and all have strongly clift shores; but as the cliffs 

 are interrupted by embayed valleys and are fronted by lagoon floors, or plat- 

 forms, at a depth of 20 or more fathoms, it foUovk^s that the cliffs were cut 

 back by waves during the same time of higher stand of the islands as that in 

 which the new embayed valleys were eroded by their streams. The clift 

 islands of the Marquesas group are exceptional in being free from reefs, 

 although nearer the equator than the abundant atolls of the Paumotus, which 

 stand about 300 miles to the southwest. 



Tutuila is fringed by a rather strong reef, but the outer edge of its remark- 

 able platform is not surmounted by a barrier reef. Tahiti has a barrier reef 

 as well as fringing reefs, and its embayments are nearly all filled with delta 

 flats, while the embayments of the other islands are not filled. It is inferred 

 from these contrasts that the date of submergence of the islands can not have 

 been contemporaneous, and hence that they were submerged by local subsi- 

 dence and not by a universal rise of ocean level. 



Presented without notes. 



Discussed by Prof. E. A. Daly, with reply by author. 



EROSIVE CLUES TO THE HIGH PLATEAUX OF UTAH 

 BY CHARLES R. KEYES 



(Ahstract) 



When the high plateaux of easte^-n Utah were first made subject of especial 

 description, the possibility' of a definite geographic cycle in land sculpture was 

 one of the earth conceptions not yet even faintly adumbrated. Omission of 

 such consideration of fundamental importance necessarily led to curious aber- 

 ration in the treatment of the phenomena presented. 



Following closely the rather unscientific Powellian policy of geological 

 saisissement, Button entirely missed the larger physiographic significance of 

 his basic observations on the prodigious amount of erosion which the Utah 

 region had manifestly undergone in relatively recent geologic times. He easily 

 fell into speculation along other lines. 



Sinre the elevations of the high plateaux are about the same as those of the 

 crest of the Rockies, the two are often closely compared. The terre pleins 

 of the plateaux and the sunnnit plain of the Cordillera are both about 12,000 

 feet above the sea. The usual inference is that through epeirogenic uplift the 



