X66 PROCEEDINGS OF THE ALBANY MEETING 



GEOLOGY OF THE LAU ISLA^'DS, FIJI 

 BY WILBUR GARLAND FOYE* 



(Adstt'act) 



The Lau Islands form a group extending for 300 miles along the 179th 

 meridian west of Greenwich, hetween the 17th and 21st parallels of south 

 latitude. They maj be grouped into three classes: (1) islands composed of 

 elevated coraliferous limestone, (2) volcanic islands, and (3) islands composed 

 of volcanic rocks and coraliferous limestone. The latter islands have, in cer- 

 tain cases, a conglomerate of coral and shell rubble mingled with rolled pebbles 

 of the underlying volcanic rock resting on an eroded surface of the volcanic 

 rock. Two hundred to three hundred feet of limestone, often with coral heads 

 in place, overlie conformably this basal conglomerate. Dr. T. W. Vaughan has 

 determined the corals as Pleistocene or Recent in date. The islands have been 

 elevated, therefore, in very recent times. In all the islands of this class 

 visited the limestones rest unconformably on an eroded surface of volcanic 

 rocks. The evidence points to subsidence during the deposition of the lime- 

 stone. 



Certain elevated masses of limestone have been eroded to submarine plat- 

 forms by atmospheric solution since their uplift. Such platforms, if produced 

 by atmospheric solution alone, should now stand near sealevel, for the feebl(> 

 wave-action behind a protecting reef can not erode to any great depth below 

 that level. It is significant that 77 per cent of the lagoon depths are between 

 10 and 20 fathoms. Such depths can only be explained by submergence, and 

 the evidence points to the fact that submergence was the result of actual 

 subsidence. 



Presented in abstract extemporaneously. 



At 1 o'clock the reading of scientific papers was discontinued and the 

 session adjourned for luncheon. 



At 2 o'clock the Society reconvened to take np the reading of scientific 

 papers. Past President Coleman presiding. 



TITLES AND ABSTRACTS OF PAPERS PRESENTED BEFORE THE AFTERNOON 

 SESSION AND DISCUSSIONS THEREON 



INTRAFORMATIOWAL STRUCTURE IN THE ORDOVICIAN LIMESTONE OF 

 CENTRAL PEXNSYLVANIA 



BY RICHARD MONTGOMERY FIELD ^ 



(Al)stract) 



This paper deals with the relative importance of ripple-marks and mud- 

 cracks in interpreting some of the conditions under which the Beekmantown, 

 Stones River, and Trenton limestones were formed. 



1 Introduced by R. A. Daly. 



2 Introduced by Percy E. Raymond. 



