1893.] NEW YOEK ACADEMY OF SCIENCES. 105 



aflforded. But such is not the case; tliey are entirely distinct, 

 the granite being younger. This conclusion is not based upon 

 actual contact relations between the two rocks, for no contact 

 was found. But it is believed tbat the marked difference in 

 petrographic character and degree of metamorphisni affords 

 sufficient evidence for regarding the fonnations as distinct. 



The granite of the main ridge was traced, with occasional 

 breaks, over a distance of ten miles, without reaching a limit. 

 The height of the ridge varies from nothing up to two hundred 

 feet, the width averaging perhaps a quarter of a mile. A 

 peculiar topographic feature is j^resented in the presence of 

 several basins in the ridge, partially enclosed by precipitous 

 walls and with flat meadow bottoms. These may represent 

 masses of limestone, that have been weathered out from the 

 surrounding granite. 



The village of Hailesboro is built upon the granite and affords 

 a favorable locality for its examination. In the angle between 

 the creek and highway, E 9, a low hill of granite shows well 

 the general character of the rock, together with a jieculiar 

 modification. The average rock is a coarse grained aggregate 

 of quartz, white feldspar, and biotite, the latter constituent 

 varying greatly in quantity, and often entirel}' absent. No 

 muscovite has been seen, even of secondary origin, and the 

 rock must, therefore, be classed as a granitite. Gneissoid 

 structure is seen in a few areas of limited extent, but is not so 

 marked as at some other localities. Near the northern edge of 

 the outcrop the granite shows a fine grained, white phase. 

 This crumbles under the hammer and looks much like a white 

 sandstone, though showing no parallel arrangement of constit- 

 uents. Microscopic examination shows it to be a fine mosaic 

 of quartz and feldspar, with numerous coarser grains of garnet, 

 often with crystal outline. That this rock is simply a peculiar 

 phase of the granite is shown by the passage of one into the 

 other by imperceptible stages. This modification of the 

 granite, which may be distinguished as granulite, occurs at 

 many points in the region, and alwaj's shows the same gi-adunl 

 transition into ordinary granite. Several patches of dark 

 silicates enclosed in the gi*anite, being sharply separated from 

 it and made up chiefly of horublende, are presumabl}' inclusions 

 brought up from deep-seated rocks. Quartz veins are abundant, 

 and represent at least two periods of fracturing and infiltration. 

 This outcrop also shows well the contact with limestone. The 

 granite breaks through the limestone causing great disturbance 

 of strike and dip, and completely enclosing masses of the rock 

 many feet in diameter. The effects of contact metamorphism 



