r52 NEW YORK STATE MUSEUM 



series, it is strange that no evidence of this is forthcoming in the 

 way of contacts or of dikes from the syenite cutting the other. 

 The more probable explanation is thought to be that we are here 

 dealing with a great area of eruptive granite which cuts and 

 becomes involved with the syenite, forming a border zone. It 

 ehould however be stated that the titanite gneisses shown here 

 are somewhat unusual, generally of no great extent, and are not 

 the usual border rocks of the syenite. 



This belt of gneisses seems prolonged to the southeast as a 

 narrow band, crossing the Kaquette between Tupper lake and 

 Kaquette pond, and expanding along the shores of Big Simons 

 pond. In this extension the titanite gneisses are not found, the 

 rocks being granitic gneiss and certain mongrel gneisses which 

 appear like somewhat weathered augite syenite, such as are fre- 

 quent in the border zone. This band appears to separate com- 

 pletely the Big Tupper lake syenite mass from that found at 

 Tupper Lake village and thence north and east. But it is the 

 latter that sends out the dikes into, and shows gradation into 

 the anorthosite; while the border zone under discussion might 

 be regarded as pertaining equally to each. The village mass 

 also, on its west side, shows a perfectly characteristic border 

 zone, and then passes into granite, precisely as does the lake 

 mass, though the former is in a difficult region and has not been 

 so carefully investigated. 



It should also be emphasized that the intervening belt under 

 discussion here, constituted of granitic gneiss and other gneiss 

 which is akin to the syenite, would be unhesitatingly classed in 

 the ordinary " gneiss " division of the Adirondacks (Kemp's series 

 1) were the neighboring syenite not present, and emphasizes the 

 view that the syenites are akin in origin and age. It should be 

 further said that this series 1, as at present constituted, in- 

 cludes many and diverse rock types. 



District between Big Tupper lake and Horseshoe pond 

 The shores of and the islands in Big Tupper lake are composed 

 of augite syenite except at the extreme upper end. For the most 

 part they are rocky, so that exposures are frequent and show well 



