ELIZABETHTOWN AND PORT HENRY QUADR.\NGLES 49 



In the Ausable quadrangle very rusty basic dikes of the syenite 

 series have been found, intrusive even in older and larger masses 

 of the same series of rocks. The basic syenitic types develop under 

 metamorphism a crumbling variety of gneiss, which on exposures 

 that have been quite thoroughly weathered may be rubbed to coarse 

 sand between the fingers. Black grains of silicates and ores then 

 separate from rusty green feldspar. 



Within the area here described all varieties of syenites show the 

 effects of crushing and the production of gneissoid foliation to a 

 marked degree and no locality can be cited free from it. Along 

 fault planes, where dynamic effects are pronounced, much secondary 

 quartz has sometimes been infiltrated and on weathering the rock 

 becomes a pronounced red, looking like a coarse, red granite. 



This so called syenite series has an exact parallel in Norway, 

 where in association with anorthosites, practically indistinguishable 

 from the Adirondack occurrences, C. F. Kolderup has established 

 the existence of others consisting of microperthite and augite. The 

 latter Kolderup calls by the new name mangerite, based on a Nor- 

 wegian locality, Manger. This duplication on opposite sides of the 

 Atlantic is an extremely interesting coincidence.^ 



The following analyses have been prepared of the syenites within 

 the area covered by the bulletin, three of the samples having been 

 taken from drill cores at Mineville. They represent the several 

 varieties as well as selections would admit. With them is also 

 placed one of a marked granitic phase, no. I, which, however, care- 

 ful study of relationships fails to prove a separate intrusive mass. 



1234 



SiO-2 '• 68.87 73-84 52.01 45-8i 



AI2O3 10-76 14. II 16.93 20-32 



FesOa 3.52 .22 .14 .53 



FeO 1-26 1. 12 10-25 8-45 



MgO 2-27 .83 2-50 6.45 



CaO 2-59 .44 6.14 7-97- 



NaoO 2-45 6.36 4.65 4-53 



1 Granitic extreme of syenite series i mile west of Mineville. Analyzed 

 by Charles Fulton. 



2 Granitic extreme of syenite series; hanging wall of magnetite. Mine- 

 ville. Analyzed by M. K. Adams. 



3 Average syenite of rocks containing the Mineville magnetite, M. K. 

 Adams. 



4 Basic syenite of rocks containing the Mineville magnetite. M. K. Adams. 



1 Kolderup, C. F. Die Labradorfelsen des westlichen Norwegens. 

 Bergen's Museum's Aarbog. 1903. p. 102. 



