. THE GREAT CENTRAL SYNCLIXE. 231 



Monson gneiss (a). The latter indurated the former and shattered it, and a 

 heavy bed of granitic fault rock (flesh-colored binary granite) is interposed. 

 Just sovith of Cooley ville, at the last house before the road crosses the Pres- 

 cott line, is an interesting section: Below is Monson gneiss (a), flat-foliated 

 but thick-bedded, regularly spotted by gi-ains of black hornblende, and 

 looking like a granite-porphyry, being much more compact and less granu- 

 lar than usual, and plainly influenced by the fiiult. The great fault up the 

 hillside is marked by about 25 feet of a granitic fault rock, at times a flesh- 

 colored binary granite, at times a hornstone of similar color or green, at times 

 a flesh-colored chloritic gneiss in structure — all these crushed and recrushed 

 and again cemented. Then comes about 10 or 15 feet of amphibolite (d), 

 also wholly crushed, and above this a buff quai'tzite, perhaps 20 feet thick, 

 followed by a great thickness of bedded gneissoid rock, granular and rusty, 

 and with its micaceous mineral wholly decomposed, which is apparently 

 identical with the chloritic sericite-schist (e) of the last section but one. 

 It repeats exactly the corresponding members of the section north of 

 Cooleyville, and this shows that nearly all the amphiboUte has here been 

 cut off on the fault. 



The eastern border beds. — At Orange Center the border beds are com- 

 pressed against the gneiss and overturned, the lowest bed wholly concealed, 

 the others greatly thinned. Just south of the river in Walnut Hill all these 

 beds reappear in force and in duplicate in a remarkable subordinate anti- 

 cline, best understood by inspection of the map (PI. XXXIV). 



The whole center of the hill is made up of the lower member, here 

 a fine-grained, thin-fissile, two-mica gneissoid quartzite (&), with garnets. 

 This is flanked on either side by amphibolite (d), then by a micaceous 

 quartzite (e), then by the mica-schist (/), which is on the east side fibrolitic. 



The narrow syncHne which separates this anticline from the gneiss on 

 the east dies out southward and, a little over the south line of Orange, lets 

 the basal member of the series come in contact with the Monson gneiss in a 

 normal manner, and it continues thus across New Salem as a broad band of 

 two-mica quartzose gneiss. 



The mica-schist — This has been described in the section above as a 

 true graphitic, spangled Conway schist. This is its character only in a 

 narrow band along the New Salem-Shutesbury line, which runs out before 

 reaching the latitude of Cooleyville on the south, and which on the north 



