Ailing — Problems of Adirondack Precambrian. 51 



not seem to have been appreciated. A similar occurrence 

 seen by the writer in the St. Regis quadrangle just south 

 of Mountain pond emphasizes this point. Here xenoliths 

 of anorthosite and foliated Grenville lie embedded in 

 quartz syenite. The hypothesis that the foliation of the 

 Grenville was entirely due to the irregular upwelling 

 of the Algoman intrusives seems to be no longer applic- 

 able to the region. 



Grenville Stratigraphy. 



It is the hope of Adirondack geologists that the Gren- 

 ville series can be "put in order." This would seem a 

 hopeless task in view of the lack of organic remains, the 

 extreme metamorphism which they have experienced, and 

 their patchy distribution. Recourse to lithological char- 

 acters and petrographic similarities is fraught with con- 

 siderable danger, but the graphite schists themselves 

 furnished more or less reliable datum planes upon which 

 the working out of the stratigraphy could be based. I. H. 

 Ogilvie 6 has already attempted to distinguish the larger 

 units of the stratigraphy. W. J. Miller 7 has listed a 

 large variety of paraschists and paragneisses, but their 

 units were far too large to be used in connection with the 

 graphite deposits. As the beds recognized increased in 

 number, it became necessary to apply names to each 

 formation to act as " handles." This proved to be a 

 difficult task, however, due to the scarcity of geographical 

 names in the sparsely settled Adirondacks and due to lack 

 of time. The following names are purely tentative ; and 

 are offered merely as suggestions for further work. 

 Table I is the result of accumulative evidence secured 

 from visiting the graphite properties in the southeastern 

 Adirondacks. Table II is the stratigraphy of the rocks 

 many miles to the north as shown on the George W. Smith 

 property south of Clintonville, Essex County (Ausable 

 sheet) in the northeastern Adirondacks. 



Stratigraphic Details. 



The graphite schists are at least two in number. The 

 upper formation, the Bear Pond schist, is an andesine- 

 orthoclase-quartz-biotite-graphite schist. It probably 

 does not extend over such an extensive area as the lower 



6 Ogilvie, I. H. : N. Y. State Mus., Bull. 96, pp. 479-483, 1905. 



7 Miller, W. J. : N. Y. State Mus., Bull. 170, p. 10, 1914. 



