BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 VOL. 4, PP. 147-166, PL. 2 FEBRUARY 25, 1893 



SOME DYNAMIC AND METASOMATIC PHENOMENA IN A 



METAMORPHIC CONGLOMERATE IN THE 



GREEN MOUNTAINS * 



BY CHARLES LIVY WHITTLE 



(Presented before the Society August 16, 189%) 

 CONTENTS 



Page 



Metamorphic Conglomerate 148 



Approximate Relation to known geologic Horizon 148 



Ottrelite Schist 148 



. Occurrence and Extent 148 



Physical and microscopic Characters 140 



Mineralogic Constituents 150 



Parallel Grouping of ottrelite Prisms 151 



Parallel Grouping of rutile Grains ■ 152 



Alteration of Ottrelite into Chlorite 152 



Relation of the two Minerals 152 



Optical Characteristics 153 



Groundmass of the Rock 153 



Mineralogic Constituents 153 



Feldspar 153 



Sericite 153 



Anatase. 153 



Rutile 154 



In General 154 



Order of Crystallization 154 



Metamorphism of the clastic Material in conglomerate Phase 155 



Occurrence • • 155 



Character of the Rock 155 



Secondary Enlargement of clastic Tourmalines 156 



Two Periods of Disturbance indicated 158 



Alteration of clastic Feldspars 150 



Clearing Action of growing Sericite 160 



Alteration of clastic Microcline into Plagioelase 161 



Chlorite Schist and Phyllite 164 



Their Plications built into secondary Albites L64 



Composition of the Groundmass 165 



* Published by permission of the Director of the IT. 8. Geological Survey. 

 XXII— Bull. Geol. Soc. Am., Vol. 4, 1892. (147) 



