VI BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



Page 

 Criteria for the recognition of various types of sand grains [discussion] ; 



by W. H. Sherzer 775 



The theory of isostacy [abstract and discussion] ; by W. M. Davis 777 



Geological progress map of Oklahoma [abstract] ; by Charles N. Gould. 777 

 Observations on rate of sea-cliff erosion [abstract] ; by Charles P. Berkey. 778 

 Climate and physical conditions of the Keewatin [abstract] ; by A. P. 



Coleman 778 



Permo-carbonic conglomerates of south Brazil [abstract and discussion] ; 



by J. B. WooDwoRTH 779 



Magothy formation of the Atlantic coast (abstract] ; by A. B. Bibbins 780 



Age of the Calciferous formation of the Mohawk Valley, New York [ab- 

 stract] ; by E. O. Ulrich and H. P. Cushing 780 



Upper Cayugan of Maryland [abstract and discussion] ; by T. Poole May- 



NARD 781 



Stratigraphic relations of the Livingston beds of central Montana [ab- 

 stract] ; by R. W. Stone and W. R. Calvert 782 



Discovery of fossils in the Quantico slate belt, and the association of vol- 

 cano-sedimentary beds with the slates of the Virginia crystalline region 



[abstract] ; by Thomas L. Watson and S. L Powell 782 



Rhode Island coal [abstract] ; by Charles W. Brown 783 



Geologic thermometry [abstract and discussion] ; by Fred E. Wright. . . 783 

 Obsidian from Hrafntinnuhyggur, Iceland [abstract] ; by Fred E. Wright. 784 

 Pegmatite in the granite of Quincy, Massachusetts [abstract and discus- 

 sion] ; by C. H. Warren and Charles Palache 784 



Origin of the alkaline rocks [discussion] ; by R. A. Daly 785 



Complex of alkaline igneous rocks at Cuttingsville, Vermont [abstract and 



discussion] ; by J. W. Eggleston 785 



Bleaching of granite at limestone contacts [abstract] ; by H. P. Cushing. . 786 

 Barite deposits of Five Islands, Nova Scotia [abstract] ; by Charles H. 



Warren 786 



Fayalite in the granite of Rockport, Massachusetts [abstract]; by Charles 



Palache 787 



Nelsonite, a new rock type; its occurrence, association, and composition 



[abstract] ; by Thomas L. Watson and Stephen Taber 787 



Regional devolatilization of coal [abstract] ; by David AVhite 788 



Microscopic study of certain coals in relation to the sapropelic hypothesis 



[abstract] ; by E. C. Jeffrey 788 



Present and future of natural gas fields in the northern Appalachians [ab- 

 stract] ; by F. G. Clapp 788 



Proceedings of the Eleventh Annual Meeting of the Cordilleran Section of the 

 Geological Society of America, held at Berkeley, California, March 25 and 



26, 1910 ; George D. Louderback, Secretary 789 



Session of Friday, March 25 789 



Election of officers 790 



Limestone plains of the interior of Bolivia [abstract] ; by J. C. Bran- 



NER 790 



New development at the mouth of the Mis-^issippi [abstract] ; by 



E. W. Hilgard 791 



Contribution to the geology of eastern Oregon [abstract] ; by E. L. 

 ICKES 791 



