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NEW YORK STATE MUSEUM 



toward the basic end of the 'granites, hence it is not surprising 

 that slight variations toward further basicity should give rise to 

 rock with little quartz, like that south of Clayton along French 

 creek. Except for this the petrographic agreement is so close in 

 all details that there seems no question as to the identity'of the two 

 rocks. • 



Alexandria syenite 



In the previous description of this syenite it has been stated 

 that an augen gneiss adjoins it on the south which was taken by 

 us in the field for a gneissoid, border phase of the rock, but that 

 Smyth dissents from this view. In the field this border rock ap- 

 pears much the more basic of the two, but closer examination 

 shows the presence of much quartz, and chemical and microscopic 

 investigation shows it to be much more acid than the syenite. 

 Analyses of each follow, with two* analyses of the general Adiron- 

 dack green syenite, thought to be represented in this district by the 

 Theresa syenite, (of which no analyses have been made) for pur- 

 pose of comparison with them. 



Si0 2 .. 



AI2O3. 



Fe 2 3 . 



FeO.. 



MgO. 



CaO.. 



Na 2 0. 



K 2 0.. 



H2O + 



H 2 0— 



Ti0 5 . , 



P 2 2 . 



CI.... 



F 



S 



MnO. 

 BaO.. 



19 

 2 

 2 



1 , 



3 



4 

 5 



58.99 

 22 



83 

 83 

 25 

 41 

 33 

 64 

 35 

 04 

 01 



59 

 10 

 40 

 08 



14 



09 



100 .30 



59-7o 



19.52 



1.89 



4.92 



•78 



3-36 



5-3i 

 4.14 



•52 



100 . 23 



63-45 

 18.38 

 09 

 69 



35 

 06 

 06 

 15 

 30 

 07 



trace 



99 .60 



66.50 

 15.66 



•75 

 .21 

 .18 

 •15 

 •74 

 .02 

 .40 

 .05 

 •7i 

 •59 

 .06 



•05 

 .18 



•03 

 •05 



33 



66.59 



14.54 

 2 .42 



2-43 

 1. 18 



2.15 



3.08 



5.62 



.46 



"!8i 

 .40 



•03 

 .06 

 .08 

 •23 

 •17 



100 .25 



1 Alexandria syenite, 3 L / 2 miles north of Redwood (8K2, Alexandria 

 sheet). E. W. Morley, analyst. 



2 Tupper syenite (laurvikose), N. Y. State Mus. Bui. 115, p. 514. 



3 Loon Lake syenite (pulaskose), N. Y. State Mus. Bui. 115, p. 514. 



4 Augen gneiss associated with Alexandria syenite, 2 miles west of north 

 of Redwood (6J2, Alexandria sheet), E. W. Morley, analyst. 



5 Picton granite, repeated from previous column of analyses. 



