r70 NEW YORK STATE MUSEUM 



8 Augite syenite (985) from the great Intrusion into anorthosite, road 



from Tupper lake to Wawbeek, ^ mile east of Halfway brook, 

 which marks the line between townships 22 and 23, Franklin co. 

 E. W. Morley analyst. 



9 Augite syenite, cut by N. Y. C. & H. R. R. R. 3^ miles north of 



Tupper Lake Junction (906) and 1 mile from the first anorthosite^ 

 outcrops, the latter being of the transition type of 905, analysis 6;. 

 A'ltamont, Franklin co. E. W. Morley analyst. 



10 Gneiss, referred somewhat doubtfully to augite syenite; occurs- 



involved with a later granitic gneiss in the border zone of the 

 augite syenite; from cut by N. Y. C. & H. R. R. R. between Fierce- 

 field and Childwold, a.nd i mile from the latter (1006); Hopkinton>. 

 St Lawrence co. E. W. Morley analyst. 



11 Augite syenite, Loon lake, Franklin co., typical. Description by H. P. 



Cushing, analysis by E. W. Morley. Geol. soc. Am. Bui. 10:177-92. 



12 Augite syenite, near Harrisville, Diana, Lewis co.; the gabbroic rock,. 



analysis 7, is a differentiation phase of this syenite. Description 

 and analysis by C. H. Smyth jr. Geol. soc. Am. Bui. 6:271-74; and 

 N. Y. state geol. 17th an. rep't 1897. p. 471-86. 



13 Augite syenite. Little Falls, Herkimer co. Description in the paper on' 



the pre-Cambrian rocks at Little Falls which accompanies this report. 

 E. W. Morley analyst. 



14 Quartz augite syenite, from border zone and accompanied by granite^ 



cut by N. Y. & Ottawa R. R. 2^ miles south of Willis pond, Alta- 

 mont, Franklin co. E. W. Morley analyst. 



The writer wishes to express his great indebtedness to Prof. Morley 

 for his hearty cooperation. Part of the above analyses were made out 

 of pure goodwill for the writer; part by order of the New York state 

 museum. 



Discussion 



Tlie gabbros are the most basic rocks of the Adirondack erup- 

 tive core, except for their own local, iron rich differentiations 

 which give rise to the titaniferous magnetite ore deposits. The 

 two analyses, 1 and 2, represent well their general composition 

 and the usual limits of their variation. 



Unfortunately, with the exception of analysis 3, no analyses are 

 available of the transition rocks between the gabbros and the 

 anorthosites, such transition rocks occurring at the borders of the 

 main anorthosite bodies as well as in smaller, separate masses, 

 though the general differentiation of the gabbro and anorthosite 

 must be regarded as having taken place below, in the parent 

 magma of both. The smaller anorthosite bodies, such as those 



