GEOLOGY OF THE NORTHERN ADIRONDACK REGION 



333 



S Augite syenite from the great intrusion into anorthosite, road from 

 Tapper lake to Wawbeek, % mile east of Halfway brook, which marks 

 the line between townships 22 and 23, Franklin co. Description by 

 Gushing, analysis by Morley. 20th An. Rep't N. Y. State Geol. 1902. 

 p.r69. 



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

 Lake Junction and 1 mile from the first anorthosite outcrops, the latter 

 being of the transition type, analysis 6 ; Altamont, Franklin CO. 

 Description by Gushing, analysis by Morley. 20th An. Rep't N. Y. 

 State Geol. 1902. p.r<;<>. 



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 Piercefield and Childwold, 

 and 1 mile from the latter ; Hopkinton, St Lawrence co. Description 

 by Gushing, analysis by Morley. 20th An. Rep't N. Y. State Geol. 

 1902. p.r70. 



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



Gushing, analysis by E. W. Morley. Geol. Soc. Am. Bui. 10:177-92. 

 VI 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 17th 

 An. Rep't N. Y. State Geol. 1899. p.471-^86. 



13 Augite syenite, Little Falls, Herkimer co. Description by Gushing, 



analysis by E. W. Morley. 20th An. Rep't N. Y. State Geol. 1902. 

 p.rG9. 



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



cut by N. Y. & Ottawa R. R. 2V 2 miles south of Willis pond, Altamont, 

 Franklin co. Description by Gushing, analysis by Morley. 20th An. 

 Rep't N. Y. State Geol. 1902. p.r69. 



Discussion. The gabbros are the most basic rocks of the 

 Adirondack eruptive 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. They are 

 quite ordinary gabbros and show no differences worthy of mention 

 when compared with most rocks of the sort. 



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 

 near Keeseville and on Rand hill in Clinton county, the latter 

 furnishing the rock whose analyses appear in column 3. are very 



