228 GEOLOGY OF OLD HAMPSHIEE COUNTY, MASS. 



The ampliibolite (f?) is a thin-fissile, often epidotic, persistent bed, not of 

 great thickness, which on Mount Grace contains a beautiful radiated tour- 

 maline, common in collections. 



The upper quartzite bed (e) is developed as a light, sandy biotite-schist 

 (— whetstone-schist) for a long distance east of the road east of Sunny 

 Valley. Northeast of Warwick Center it is a thin-bedded quartzite, exactly 

 like the Bemardstou quartzite. It is generally a gray whetstone-schist. 



These tliree beds dip east beneath, and form a narrow border to, the 

 great area of mica-schist (/), which has a width eastward of nearly 4 miles. 



Structure. — The lower beds dip east beneath the mica-schist. The 

 latter strikes north-south and has high and irregular dips, being crumpled 

 up into a mass from which one can gain no idea of its real thickness. 



The lower beds run south normally until, opposite Mount Grace, they 

 are thrown into great confusion. An east-west fault runs through the north 

 brow of the mountain and far east. South of this and on the slope east of 

 Mount Grace the lower beds are greatly crumpled, while Mount Grace 

 itself is formed by the westward projection and folding of these three beds, 

 and traces of this disturbance are seen all through the village of Warwick, 

 the rocks being so crumpled that the ampliibolite runs south in three long 

 bands to Hasting's pond. On this bend north of the pond a vein of coarse 

 epidote-garnet rock with fine quartz crystals is found 



Farther on the lower beds regain their regular posture and run south 

 to Harris's pond, in the southwest corner of the town, where the Wendell 

 anticline, already described (p. 217), branches off. A little to the east a 

 minor fold brings up the ampliibolite (f?) through the mica-schist (/), and on 

 either side of it the whetstone-schist (e), in a narrow anticline which runs 

 down Brush Valley, crosses the river east of West Orange and continues 

 south, ending in the west part of Orange. 



The eastern border of quartzites and ampliiholites. — At the east side of 

 Prospect street, in Orange, the ampliibolite (d) rests directly against the 

 Monson gneiss, with steep eastward dip, as if it went under the latter. This 

 "fan structure" is common all around the Orange basin. 



The beds below the amphibolite are faulted out of sight — north and 

 south — for a long distance. The latter is reduced to a small thickness here, 

 perhaps 30 feet; and the upper quartzite (e) is still more reduced, being here 

 a compact quartzite ; a mile north it is a fine-grained micaceous quartzite. 



