TITLES OF PAPERS PRESENTED 53 



FURTHER DISCOVERIES IN THE TACONIC MOUNTAINS 

 BY ARTHUR KEITH 



Presented by title in the absence of the author. 



PRELIMINARY GEOLOGICAL MAP OF THE NAVAJO-MOKI RESERVATION 

 BY HERBERT E. GREGORY 



Presented in abstract without notes. 

 The section adjourned. 



TITLES OF PAPERS PRESENTED BEFORE THE THIRD SECTION AND NAMES OF 



DISPUTANTS 



The third section of the Society convened at 2.35 o'clock, with Vice- 

 President I. C. White as Chairman and H. B. Patton serving as Secre- 

 tary. The section took up the reading of the papers in Group C, as fol- 

 lows: Petrologic, Mineralogic, and Economic: 



THE VARIOUS FORMS OF SILICA AND THEIR MUTUAL RELATIONS 

 BY CLARENCE N. FENNER 



Eead in full from manuscript. Discussed by F. E. Wright. 



THE INDEX-ELLIPSOID IN PETROGRAPHIC-MICROSCOPIC WORK 

 BY FRED E. WRIGHT 



Eead in full from manuscript. Discussed by J. E. Wolff and E. B. 

 Mathews. 



IGNEOUS COMPLEX OF HIGH TITANIUM, PHOSPHORQUS-BEARINQ ROCKS OF 

 AMHERST-NELSON COUNTIES, VIRGINIA 



BY THOMAS L. WATSON AND STEPHEN TABOR 



Eead by title in the absence of the authors. 



PETROLOGY OF A SERIFS OF NEPHELINE SYENITE, CAMPTONITE, MONCHI 

 QUITE, AND DIABASE DIKES IN MIDDLE SHENANDOAH VALLEY, VIRGIN I l 



BY THOMAS L. WATSON AND JUSTUS H. CLINE 



Eead by title in the absence of the authors. 



THE NORTHUMBERLAND (NEW YORK) VOLOANIC PLUQ 

 in ii. P, GUSHING 



