620 PROCEEDINGS OF THE BALTIMORE MEETING 



SOME DISTINCTIONS BETWEEN MARINE AND TERRESTRIAL CONGLOMERATES 



BY JOSEPH BARBELL 



[Abstract] 



The problem was approached by studying the effects of shore, as compared 

 with subaerial, activities upon the production, transportation, and deposition 

 of gravel. It was determined that the truly terrestrial forces produce vastly 

 more gravel, spread it far more widely, and provide more opportunities for 

 deposition than do the forces of the littoral zone. Conglomerate formations, 

 therefore, should be dominantly of terrestrial origin. In order to determine, 

 however, the mode of origin of particular examples, definite criteria must be 

 drawn between the two classes. It was shown that the thickness was one of 

 the most important of these, marine conglomerates, except under local and spe- 

 cial circumstances, being limited to considerably less than 100 feet in thick- 

 ness, terrestrial conglomerates, on the other hand, being frequently measured 

 in hundreds and occasionally in thousands of feet. 



Attention was next turned to the significance of the intercalated non-con- 

 glomeratic beds and the relations to the under- and over-lying formations, with 

 the conclusion that the characteristics of the associated strata are frequently 

 of high supplemental value for determining the mode of origin. 



Applications of the conclusions were made to several conglomeratic forma- 

 tions. 



Professor BarrelFs paper was discussed by G. K. Gilbert, J. Barrell, 

 and W. H. Hobbs. 



REPORT OF COMMITTEE ON GEOLOGIC NOMENCLATURE 



Arthur Keith reported that the Committee on Geologic Nomenclature 

 had organized, with T. C. Chamberlin as chairman and Arthur Keith as 

 secretary. 



The committee is constituted as follows : 



For the Geological Society of America : T. C. Chamberlin and W. B. Scott. 

 For the U. S. Geological Survey: Arthur Keith and David White. 

 For the Association of State Geologists : J. M. Clarke and E. A. Smith. 

 For Canada — Geological Survey : F. D. Adams. Other official surveys : W. G. 

 Miller. 



For Mexico: J. G. Aguilera. 



The following papers were read by title : 



FIRST CALCAREOUS FOSSILS AND THE EVOLUTION OF THE LIMESTONES 

 BY KEGINALD A. DALY 



This paper has been published as pages 153-170 of this volume. 



