THICKNESS. 433 



Castlcton Brook, instead of running into Otter Creek as appears the most natural 

 passes through this gorge in the mountains towards Lake Champlain. It thus forms 

 an excellent passage for the convenience of transportation between the settlers of Otter 

 Creek and Champlain valleys. So unnatural does this chasm appear that we are almost 

 inclined to suppose that it is the result of a dislocation. A hasty examination has not 

 afforded us any proof, however, of the occurrence of different rocks or of a different posi- 

 tion of them upon the two sides of the gulf. For all the details respecting the region 

 between Rutland and Lake Champlain, we refer to the description of Section VI. 



West of the clay slate of the Georgia group in Sudbury the talcoid schist is found 

 dipping beneath it, forming a belt towards half a mile wide. "We have also found it in 

 the northwest and southwest parts of Hubbardton ; hence we suppose these ledges, in con- 

 nection with other layers of remarkably well defined talcoid schist in Fairhaven, to form 

 a single belt of rock, entirely independent of that east of the Georgia slate, unless the 

 two deposits be connected together beneath the Georgia slate. As both bands dip in the 

 same direction, the connected synclinal must be an inverted one. 



Thickness. The thickness of the talcoid schists upon Greylock is 2,000 feet. Upon Mt. 

 Eolus they are 498 feet thick. How much has been removed by erosion it is impossible 

 to say. The thickness of the band of schists in Danby, by a rough trigonometrical calcu- 

 lation is 1354 feet. The average thickness of the talcoid schists of the Taconic mountains 

 in Vermont must be greater than 2,000 feet. 



Mineral Contents. 



Native gold is found in the alluvium derived from the abrasion of the talcoid schists. We have known 

 of its existence in Danby, and the investigations of Mr. Hager show that it is also found in Dorset and 

 Sandgate. Probably, also, the gold in Mt. Tabor, Manchester, Shaftsbury, and Bennington, was originally 

 derived from veins of quartz in these schists. For the particulars respecting the gold in this rock, we refer 

 to the Report upon Economical Geology. 



Large masses of milk quartz are abundant in the talcoid schists. It occurs in nodular masses, often 

 mixed with chlorite and the carbonates, and oxyds of iron and manganese. Bowlders of white quartz are 

 very common over the surface which is underlaid by this formation. 



Black tourmalin, octahedral iron and pyrites also occur in the talcoid schists. 



Organic Remains. 



Two species of fossils have been found in Ira, in beds of limestone associated with the talcoid schists. 

 They are a few small encrinal rings, and what resemble an Euomphaloid shell. The specimens are too in- 

 distinct for recognition, but are sufficiently plain to allow us to place this formation among the fossiliferous 

 rocks. The specimens are from Ira and West Eutland. 







Geological Position and Equivalency. 



As stated in the description of the stratigraphical position of the talcoid schists, the 

 |iiestion of their geological position depends upon the nature of the disturbing forces. 

 If the Eolian and Equinox range has been elevated to its present position from a great 

 depth, then the talcoid schists capping the marbles belong to the same belt as the talcoid 

 schists on the range of mountains further west, which we have often called the Taconic 

 range. The more we reflect upon the subject, the more evident does it appear that these 

 two bands of rock are the same, and are conseopuently newer than the Eolian limestone. 



