66 PEOCEEDIXGS OF THE PRI^-CETOX MEETING 



Discussion 



Prof. A. P. Coleman : One can not expect exact accordance between the 

 ice-lobes and areas of elevation. In general the ice-covered regions have 

 risen — for example, America, Patagonia, and northeastern Europe. 



Doctor Spencer replied as follows : It is significant that their observations, 

 indicating the recent measured deformation of the land as being independent 

 of the retreat of the ice-sheet, is in conformity with the relationship between 

 the anomalies of gravity and the earth movements— investigations by entirely 

 different methods. The great earth movements are not as extensive as hinted 

 by the ice-sheet. The ice-covered areas show subsidence and also deforma- 

 tion. The mere occurrence of deformation in lately ice-covered areas is no 

 proof of the tilting being due to the removal of the glacier. Deformation 

 occurs in the Appalachian belt south of the ice-sheet, which could not have 

 affected it. 



Further remarks were made by Mr. F. B. Taylor. 



ORIGIX OF DOLOMITE 

 BY FBANCIS M. VAN TUYL " 



(Adstract) 



The theories of the origin of dolomite and the experimental evidence of its 

 formation were briefly discussed. Recent studies of the dolomites of the 

 Upper Mississippi Valley for the Iowa Geological Survey, supplemented by 

 independent observations on the dolomitic formations of the Appalachian 

 region, have furnished evidence that the great majority of '^i >lomites have 

 probably resulted from the secondary alteration of limestone. In most cases 

 the alteration certainly took place benearli the sea. 



Presented by title in the absence of the author. 



FLATTEXIXG OF LIMESTOyE GRAVEL BOULDERS BY SOLUTIOX ^'> 



BY JOHAN AUGUST UDDEN 



(Presented hy title before the Society, December St, 1913) 



Contents „ 



Page 



General statement 66 



Origin of the gravels 67 



Description of different kinds of flattening 67 



Conclusions 67 



General Statement 



Some gravels occurring in the lower valley of the Rio Grande River in 

 Texas consist of white limestone derived from the Comanchean, and also in 

 part from the Pennsylvanian, found in the westernmost part of the State. 



IS Introduced by .Tames F. Kemp. 



19 Manuscript received by the Secretary November 19, 1913. 



