POSITION. 497 



The presumption then, is rather strong that the Connecticut River band of clay slate is 

 of Devonian age. One cannot, however, but feel some doubts whether the Bernardston 

 rocks are conformably stratified with the great body of slate, and whether we do not need 

 more fossils, to speak with much confidence of the identification of the Bernardston with 

 Onondaga limestone. But there is another spot, just without the limits of Vermont, in 

 Canada, where stronger evidence is found of the Devonian character of the clay slate. 

 If the thirteenth of our sections be examined, as well as Figs. 267 and 268, we shall see 

 on the west side of Lake Memphremagog, a bed of limestone interstratified with the slate, 

 and that some of the slate, as in Bernardston, lies above the limestone. If we follow these 

 rocks northerly into Canada, as far as Owl's Head, we shall find there several fossils, which 

 palaeontologists refer to the Devonian, and which have been described under Part II. 

 They doubtless could be found in the southern prolongation of the limestone in Vermont, 

 but we have been unable to find the time necessary for a careful examination. The facts 

 we have stated, however, make it probable that the second belt of clay slate, running from 

 Memphremagog through the central part of Vermont, as far as Barnard, is of Devonian 

 age. As to the third belt, further west, we have made no discoveries, but the presumption 

 is that it is of the same age. 



The relative position of the clay slate and the micaceous and talcose schists is well 

 shown on the geological map and sections. On the map it will be seen that the two prin- 

 cipal ranges of the slate form bands on the margins of the calciferous mica schist ; and if 

 the sections be consulted, it will be seen from the dip of the slate, that it lies above the 

 schist in every case except on Section VII, where the slate on the west side of the schist 

 in Bethel dips slightly under it. But this single exception, easily explicable either by 

 supposing some local disturbance, or a folding of the strata, such as brought the schist 

 uppermost, is not sufficient to disprove the conclusion from all the rest, that the slate is 

 the newest rock. And who can doubt that it once mantled over the schist ? If so, how 

 enormous must have been the amount of erosion to form the present surface, as is shown 

 on Sections VII, VIII, IX, and X, where the thickness of the upturned edges of the schist 

 is 9, 13, 9i, lOi miles, or average 10.5 miles. And when we look at these sections, espe- 

 cially at Nos. VIII, IX, and X, and see only a single anticlinal and no synclinal, it seems 

 difficult to avoid the conclusion that we have only a single fold. Yet the enormous thick- 

 ness that would thus be given to the strata not less than 25000 feet seems strongly to 

 militate against such a view. Indeed the subject is one encumbered with difficulties. 

 But we have in another place given our views concerning it. 



The position of the clay slate in respect to the talcose schist is also clearly seen on the 

 sections. With one exception, on Section X, in Hardwiek, it dips under the schist, 

 though both the rocks are almost perpendicular. Consequently the talcose slate must be 

 the newest rock, setting aside inversions. There seems no way to avoid this conclusion 

 but by denying that the slaty and schistose structure correspond to the planes of stratifi- 

 cation, or by resorting to faults and vertical shifts and inverted dips. Yet to admit that 

 the talcose schist is newer than the clay slate, does not correspond with the conclusions 

 that have been reached by following up the series of rocks from the Champlain valley, or 

 with those of the eminent geologists who have charge of the Canada Survey. They make 

 the talcose schists a part of their Quebec group, which they place at the bottom of the 



