196 GRANITES AND GRANITIC VEIN-STONES. [XL 



line limestone is mixed with grains of greenish pyroxene, and 

 includes nodular granitic masses of white crystalline orthoclase 

 with quartz, enclosing large plates of graphite, crystals of horn- 

 blende, and more rarely of apatite. These associations of min- 

 erals are met with in the granitic veins of the Laurentian 

 limestones, to be noticed elsewhere. The limestone of Lewis- 

 ton, however, appears to be included in the great mica-schist 

 series of the region ; where similar beds, though less in extent, 

 are met with in various places, sometimes associated with 

 pyroxene, garnet, idocrase, and sphene. A thin band of im- 

 pure pyroxenic limestone, like that of Lewiston, occurs with 

 the mica-schists on the Maine Central Railroad, near Danville 

 Junction ; and beds of a purer crystalline limestone were for- 

 merly quarried in the southeast part of Brunswick, where they 

 are interstratified with thin-bedded dark hornblendic and mica- 

 ceous gneiss, dipping southeast at a high angle. 



19. At Danville Junction strata of hornblendic and mica- 

 ceous gneiss, passing into mica-schists, dip southeast at moder- 

 ate angles, and include huge veins of endogenous granite. Two 

 of these appear in the hill just south of the railroad-station, 

 apparently running with the strike of the beds. They are 

 seen to rest upon the mica-schist, and in one of them a mass of 

 this rock, three feet in width, is enclosed like a tongue in the 

 granite, which has a transverse breadth of about seventy-five 

 feet. Notwithstanding the apparent intercalation of these 

 granitic masses, the proof of their foreign origin is evident in a 

 transverse fracture and slight vertical dislocation of the mica- 

 schist, around the broken edges of which the granite is seen to 

 wrap. The endogenous character of this granite is well shown 

 by its banded structure ; belts of white quartz some inches 

 wide alternate with others of coarsely cleavable orthoclase, 

 while other portions hold black tourmalines and garnets of 

 considerable size. 



The evidence of disturbance of the strata in connection with 

 these endogenous granites is seen on a large scale at the falls 

 of the Sunday River in Ketchum. There, mica-schists and 

 gneisses, similar to those already noticed, enclose great 



