TITLES AKD ABSTKACTS OF PArERS 71 



Mr. W. Elmer Ekblaw remarkecl : I wish to state that another center ot! 

 postglacial uplift is probably located in Greenland or Ellesmere Land. The 

 reports of nearly every expedition to those lands call attention to the raised 

 beaches and wave-cut terraces along the coast. Wegener, geologist of the East 

 Greenland Danish Expedition, speaks of such a beach on the northeast coast 

 of Greenland more than 650 feet above sealevel. Schei speaks repeatedly of 

 the raised beaches along the west coast of Ellesmere Land and the east coast 

 of Axel Heiberg Land. Attention has many times been called to the numerous 

 raised beaches of West Greenland and East Ellesmere Land. 



PALEOGEOGRAPHY OF MISSOURI 

 BY E. B. BRANSON 



The author presented a series of maps representing various seas which have 

 occupied Missouri during geologic time and discussed some of the more impor- 

 tant sedimentary breaks. 



Presented in full extemporaneously. 



The KSociety adjourned soon after noon and reconvened at 2.30 p. m., 

 with President Adams in the chair, and proceeded according to the 

 printed program. 



TITLES AXD ABSTRACTS OF PAPERS PRESENTED AT THE AFTERNOON SESSION 

 AND DISCUSSIONS THEREON 



SUBSIDENCE OF REEF-ENCIRCLED ISLANDS 

 BY W. M. DAVIS 



{Abstract) 



Darwin gave two kinds of evidence in supporting his theory of upgrowing 

 coral reefs on intermittently subsiding islands : First, his theory replaced 

 unexplained confusion by reasonable order ; second, it accounted for. the sys- 

 tematic distribution of the reefs known in Darwin's time. Dana added the 

 important independent confirmation given by the embayed shorelines of reef- 

 encircled islands. Additional verification of subsidence is found <1) in the 

 physiographic interpretation of the slopes of reef -encircled islands, which gives 

 a much better estimate of reef thickness than the depth of barrier reef lagoons ; 

 (2) in the geological interpretation of the unconformable contacts of reef lime- 

 stones elevated or at sealevel, with their eroded foundations; this important 

 matter has been very generally neglected; it applies especially to the uncon- 

 formable fringing reefs of the Philippines, admirably shown on recent Coast 

 Survey charts; (4) in the natural explanation of the disappearance of the 

 detritus that has been eroded from the central islands of barrier reefs; the 

 volume of the detritus is in some instances from 30 to 80 times as great as 

 the volume of the reef -inclosed lagoon; (5) in the absence of reefs on coasts 

 of emergence; (6) in the unequal depths of lagoons and submarine banks. 



A liberal measure of subsidence being thus indicated by various lines of 



VII — Bull. Geol. Soc. Am., Vol. 29, 1917 



