PALEOZOIC TIME — LOWER SILURIAN. 



521 



deposition from the beginning of the Cambrian to the close of the Lower 

 Sikirian; and it was a very long era, possibly as long as all time that 

 has since elapsed. Mountain-making finally ensued, producing, among its 

 effects, the Taconic Mountain Range along western and northwestern New 

 England, and also the Cincinnati geanticline, besides uplifts in Nova Scotia 

 and New Brunswick. Moreover, there is probable evidence that the Taconic 

 Range at the north was but one of a series along the Atlantic border. 



The Taconic Range and system. — Some account of the Taconic Range 

 has been given on pages 386, 387. There were great flexures, great 

 faults, and general metamorphism. Fig. 730 represents a section, by 

 Selwyn, extending, near Quebec, from Montmorenci Falls on the northwest 

 and crossing the north channel of the St. Lawrence to Orleans Island. 



N.W. I II in S.E. 



Faulted and plicated rocks from Montmorenci Falls to the island of Orleans and beyond. Vertical scale, 500 



feet = l inch ; horizontal scale, I5 miles = 1 inch. Selwyn. 



The falls are to the left at F, and I marks the line of one fault. To the 

 left of this fault-line are Archaean rocks overlaid horizontally by 50 feet of 

 Trenton limestone. To the right of it there are Lower Silurian rocks, in a 

 plicated condition, from the Calciferous and Chazy (Quebec group, /, /, /) at 

 the bottom, through the Trenton limestone (a, a, a) to the Utica and Hudson 

 shales (c, c, c), the upper of these rocks making the bottom of the north 

 channel of the river. To the right, at II, there is a second fault, the main 

 fracture ; and at III, a third fault. Between the two is Orleans Island, the 

 beds numbered 6 containing Utica Graptolites ; and 1 to 5, those of the so- 

 called Levis formations of the Quebec group of the age of the Calciferous 

 and Chazy. 



From this region faults continue in a south-by-west direction, through 

 Vermont and eastern - New York. They are conspicuous in Vermont, at 

 Snake Mountain, in Addison County, and also south of Shoreham, where the 

 red sandrock rests on Hudson shales (Wing) ; and in New York at Bald 

 Mountain, and elsewhere in Washington County, near Rhinebeck on the 

 Hudson, and in Dutchess County ; and also in New Jersey, a mile west of 

 Otisville, and at the Lehigh Water Gap (G. H. Cook). 



Fig. 731 represents the fault at Snake Mountain, as given by A. Wing 

 (1877). To the right of F is the south end of the ridge of Cambrian red 

 sandrock, called Snake Mountain ; to the left are Lower Silurian formations 



