58 PROCEEDINGS OF THE PRINCETON MEETING 



TITLES AND ABSTRACTS OF PAPERS PRESENTED IN GENERAL SESSION AND 



DISCUSSIONS THEREON 



IMPROVEMENTS IN METHODS OF INVESTIGATING HIGHLY CARBONIZED 

 MATERIALS AND THEIR BEARING ON THE MODE OF DEPOSITION OF 

 COAL 



BY EDWARD CHARLES JEFFREY " 



(Abstract) 



By radically new methods of procedure, wbieli have been developed as the 

 result of long experiment, it has been found possible to secure transparent 

 sections of the hardest and most highly carbonized anthracites. The results 

 are of considerable interest as showing the mode of formation of coal in 

 general and particularly of anthracites. The present communication deals 

 particularly with the anthracitic coals of Pennsylvania, although anthracitic 

 coals of widely different geographical areas and geological horizons have like- 

 wise been studied. 



Presented by title in the absence of the anther. 



ORIGIN OF OOLITES AND THE OOLITIC TEXTURE IN ROCKS 

 BY THOMAS CLA.CHAB BEOWN " 



(Abstract) 



A brief historical review of the study of oolites was given, including refer- 

 ences to the earliest published papers, the theories of organic origin, the 

 theories of chemical origin, and the artificial production of oolites. 



The microscopic structure of oolites was described as follows : Recent oolites 

 from Salt Lake; calcareous oolites from the Cambrian and Ordovician; dolo- 

 mitic oolites from the Ordovician ; siliceous oolites from the Ordovician and 

 Tertiary ; Clinton oolitic iron ore fi-om the Silurian. 



An argument was then advanced to show that all of these oolites are of 

 chemical origin, fonned, first, as calcareous oolites, and then changed by re- 

 placement to their present condition. 



Presented in abstract from notes. 



Discussion 



Dr. C. A. Davis : In work on the formation of Chara marls in MicMgan 

 it was found that the Ca CO3 was precipitated from water which was not 

 saturated with Ca CO3. and that segregation by plants was essential in the 

 formation of the deposit. This segregation was selective for the calcium and 

 magnesium and neglected dissolved iron compounds also in the water in con- 

 siderable quantity. 



1* Introduced by David White. 

 ^ Introduced by Florence Bascom. 



