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FOLDED BOOKS. 



Beginning at the left hand or west end of the sketch below, we have represented, at a, a 

 few fossiliferous strata, lying upon hypozoic rocks, with a moderate easterly dip, having 



experienced no other disturbance than an elevation of their western side. Proceeding 

 easterly, we come to a fault, b, along which the rocks lying east have been raised, so as to 

 bring those older than a into view ; yet as they have about the same easterly dip, and the 

 fault is hidden by detritus, the fossils alone inform us that they are older. We suppose, 

 too, that they may have an inverted dip ; that is, have been thrown over, so as to bring 

 the newer strata at the bottom. We have represented two folds, c and d, of these rocks, 

 and then a second fault, e, succeeded by a synclinal fold, /, followed by rocks, it may be 

 older, it may be newer, but essentially conformable to those between the faults. The line, 

 1, 2, represents the present surface, and the dotted curves above this line show the surface 

 as it was after the original plication, before erosion had taken place. These curves are 

 represented as extending below the bottom of the section, to show into what position the 

 plication of strata would bring them could we get at them deep in the earth. Beyond f, 

 we have shown a broad anticlinal, g, which may or may not be inverted, though in the 

 synclinal, /, inversion is manifest. Beyond g, we have drawn three folds, h, i, Jc, exactly 

 alike, supposed to have occurred in the same homogeneous rock, so that when erosion has 

 swept off the curves down to the line, 1, 2, the rocks would show merely a succession of 

 perpendicular strata, exactly alike, and we could not tell how many folds were present. 

 Beyond #, we have shown a mass of unstratified rock, I, lying beneath the stratified ; the 

 latter resting upon the former with outward dips, as if the unstratified mass had been 

 protruded from beneath. More commonly however, in Vermont, and indeed through the 

 whole country, the unstratified rocks occur in thick beds in the stratified, with the same 

 dip, as shown at m. 



Now this section gives a general idea of the leading facts which geologists suppose may 

 be seen in crossing the northern part of Vermont, from Lake Champlain to Connecticut 

 River. From a to b, for instance, we have some of the oldest fossiliferous rocks (Potsdam 

 sandstone, calciferous sandstone, &c.) lying upon hypozoic gneiss. Then comes an uplift 

 along the fault, b, which brings up perhaps the primordial zone of Canada, which embraces 

 rocks at least as old as the Potsdam sandstone, and as Professor Emmons thinks, those 

 still older, especially on the second fold, d; for both folds may have inverted dips. The 

 synclinal fold, /, may represent the talcose schists west of the Green Mountains, whose 

 age, as they have no fossils, is only conjectural. The broad anticlinal fold, g, resembles 

 that of the Green Mountain range in some places, where we find several varieties of rock 

 folded together, generally with inverted dips. The succession of folds, h, i, k, may repre- 

 sent the wide belt of talcose schist generally found along the eastern side of the Green 



