BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



Vol. 18, pp. 477-492, PL. 53 DECEMBER 18, 1907 



ASYMMETEIC DIPPEEENTIATION IN A BATHYLITH OF 

 ADIEONDACK SYENITE * 



H. P. GUSHING 



(Bead before the Society December 29, 1906) 



CONTENTS 



Page 



Introduction 477 



General description 478 



The normal syenite 478 



The basic syenite 479 



The granitic syenite 480 



Border relations between the syenite and the granite-gneiss 480 



Border relations between the syenite and anorthosite 481 



Soaked anorthosite 482 



The anorthosite outlier in Litchfield parlj; 483 



Relations of the syenite to the Grenville 483 



Summary of field relations 484 



Chemical evidence 484 



Chemical analyses and discussion 486 



Introduction 



Of late years much evidence has accumulated to the effect that, under 

 deep-seated conditions of igneous intrusion, not only is contact action 

 "widespread and on a large scale, but also that rock injection and rock 

 assimilation are equally, or even more, pronounced. During the field 

 vsrork of the special committee on the correlation of the pre-Cambrian 

 rocks of the Adirondack mountains, the original Laurentian area and 

 of eastern Ontario, it was noteworthy that in both areas visited such 

 phenomena were prominently to the fore. This paper deals with one 

 of the specific instances examined by the committee, an asymmetric 

 bathylith of syenite occurring in the mid-Adirondack region, whose 



• Published by permission of tbe New York State Geologist. 



Manuscript received by the Secretary of the Society from the Censor November 6, 1907. 



XLII— Bull. Geol. Soc. Am., Vol. 18, 1906 (477) 



