GEOLOGY OF THE NORTHERN ADIRONDACK REGION 297 



resemblance to conglomerates. To a minor degree the same sort 

 of thing is shown in the gneisses, two adjacent bands of different 

 brittleness showing the more brittle ruptured and the other 

 squeezed into the break. This has often happened to the basic 

 bands in the acid gneisses for example. On a yet smaller scale it 

 is often shown among the various minerals of a single rock. 



Along the eastern border of Franklin county, extending north- 

 ward for a few miles from Franklin Falls, are considerable 

 masses of a coarse, rusty brown rock which consists of little else 

 than quartz and microperthite feldspar. The quartz is in flattened 

 lenses or spindles up to an inch or two in length, all with the 

 same orientation, and surrounded by a mosaic of microperthite. 

 The belt adjoins a belt of Grenville rocks which includes lime- 

 stones; and Kemp interprets the rock as a recrystallized and 

 squeezed conglomerate. 1 While this view may be the correct one, 

 it is desired to call attention to the fact that the belt is also 

 in close association with a mass of augite-syenite belonging to 

 the later eruptive series, that much of this rock possesses the 

 same spindle quartz, and that much of it consists of little else 

 than feldspar and quartz. The resemblance is so close that the 

 writer's disposition has been to refer the rock to these syenites, 

 as a somewhat aberrant member, and this alternative view is 

 thought worthy of record. 



In nearly all exposures of the Grenville rocks there is found 

 an admixture of red, gray and black gneisses which have the 

 composition of igneous rocks, granites, syenites, diorites and 

 gabbros and are thought to be such in a much metamorphosed 

 condition, though for the most part they have lost all trace of 

 the structures and textures of such rocks and possess an evenly 

 granular texture, due to thorough crushing or granulation of 

 their minerals, accompanied by a certain amount of recrystal- 

 lization. They now form red, orthoclase gneisses, amphibolites, 

 and gray to black, granular gabbroic gneisses. They are usually 

 so involved and interbanded with the sedimentaries as to appear 



1 Am. Ass'n Adv. Sei. Proc. 49:169. 



