400 STRATIGRAPHICAL GEOLOGY. 



On Section I, in the eastern part of the area, an anticHnal brings up 

 gneiss and hornblende schist. The same is true in Massachusetts to the 

 south, and at West Brattleboro', on Section II, to the north. This is 

 the same with the granite of Black mountain in Dummerston. The same 

 three sections allow certainly of a synclinal west of this anticlinal, nar- 

 rowing on Section II. It is known to extend as far north as New Fane 

 and Dummerston. On our revised Section III, in Westminster, observa- 

 tions are wanting on this formation ; but in Section IV, of Vermont, the 

 dip is altogether monoclinal, with the average easterly dip of 60°. This 

 being the narrowest part of the formation, I calculated the thickness here, 

 in the report upon the geology of Vermont,* finding it to be 4800 feet. 

 It was presumed the narrowness of the band might indicate its true thick- 

 ness, without any repetition, such as occurs almost everywhere else. Es- 

 sentially the same state of things is believed to occur on our No. IV in 

 Springfield. Section V crosses Mt. Ascutney, an eruptive mass in the 

 midst of the mica schist, and therefore teaches nothing concerning this 

 rock. I believe the strata on both sides of Ascutney are monoclinal, and 

 dip easterly. But we have stated evidence of the existence of two anti- 

 clinals in this rock on Section V in Cornish, besides the possible inverted 

 synclinal to the east of the last ridge. The western arm of this formation 

 is crossed by this section in Reading, where it may be a synclinal of lim- 

 ited extent. 



Section VI first gives us an idea of this formation where it is very 

 broad. There would seem to be a synclinal of this schist in Hartford, — 

 clay slate to the east and a Coos micaceous quartzite to the west, — the 

 same range with that holding the copper and pyrrhotite ores to the north 

 at Copperas hill. It is very likely a fault occurs west of this cjuartzite. 

 The Calciferous group following in Pomfret is largely composed of lime- 

 stone as far as to the argillaceous schists in Barnard marking the western 

 limit of the formation. In this area there arc two anticlinals and three 

 synclinals, the last joining a faulted fragment. Section VII shows the 

 Coos quartzite, extending as far as the eastern part of Strafford, occupy- 

 ing a place between the clay slate, which usually adjoins the Calciferous, 

 and the Calciferous itself, with a uniform, probably inverted easterly dip. 

 A fault may, perhaps, separate it from the Calciferous, which consists of 



*VoI. ii,p. 617. 



