J. D. Dana on American Geological History. 321 



between the Upper and Lower Silurian beds of Gaspe, to the 

 north. Another epoch of disturbance, still more marked, pre- 

 ceded, according to Mr. Logan, the Carboniferous beds in those 

 northeastern regions ; and New England, while a witness to the 

 profound character and thoroughness of the Appalachian revo- 

 lution, attests also to the greater disturbance towards its northern 

 limits. Some of the Carboniferous strata were laid down in 

 Ehode Island as clay and sand and layers of vegetable debris : 

 they came forth from the Appalachian fires as we now have 

 them, the beds contorted, the coal layers a hard siliceous an- 

 thracite or even graphite in places, the argillaceous sands and 

 clays crystallized as talcose schist, or perhaps gneiss or syenite. 



These very coal-beds, so involved in the crystalline rocks, are 

 part of the proof that the crystallization of New England took 

 place after the Coal Era. Fossils in Maine, Vermont, Canada, 

 and Massachusetts add to the evidence. The quiet required by 

 the continent for the regular succession and undisturbed condi- 

 tion of the rocks of the Silurian, Devonian, and Carboniferous 

 formations, shows that in neither of these ages could such vast 

 results of metamorphic action and upheaval have taken place. 



The length of time occupied by this revolution is beyond 

 estimate. Every vestige of the ancient Carboniferous life of the 

 continent disappeared before it. In Europe, a Permian Period 

 passed, with its varied life ; yet America, if we may trust nega- 

 tive evidence, still remained desolate. The Triassic Period next 

 had its profusion of living beings in Europe, and over two thou- 

 sand feet of rock; America through all, or till its later portions, 

 was still a blank : not till near the beginning of the Jurassic 

 Period do we find any traces of new life, or even of another 

 rock above the Carboniferous. 



What better evidence could we have than the history of the 

 oscillations of the surface from the earliest Silurian to the close 

 of the Carboniferous Age, and the final cresting of the series in 

 this Appalachian revolution, that the great features of the con- 

 tinent had been marked out from the earliest time ? Even in 

 the Azoic, the same northeast and southwest trend may be ob- 

 served in Northern New York and beyond Lake Superior, show- 

 ing that, although the course of the great Azoic lands was partly 

 east and west, the same system of dynamics that characterized 

 succeeding ages was then to some extent apparent. 



The first event in the records after the Appalachian revolution, 

 was the gathering up of the sands and rolled fragments of the 

 crystallized rocks and schists along the Atlantic border into 

 beds ; not over the whole surface, but in certain valleys, which 

 lie parallel with the Appalachian chain, and which were evi- 

 dently a result of the foldings of that revolution. The beds are 

 the red sandstones and shales, which stretch on for one hundred 



SECOND SERIES, VOL. XXII, NO. 66. — NOV., 1856. 



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