228 The Physical History of the Trias 



general north and south direction, may indicate the existence 

 of lines of displacement. Until such faults have been shown 

 to exist, however, we can only look upon these shales and 

 sandstones as a continuous series of estuary deposits, slowly 

 accumulated during long ages of subsidence. Admitting this 

 view, we cannot estimate the thickness of these beds at less 

 than twenty-five thousand feet. Such an immense deposit of 

 sediments, bearing through a great part of their thickness the 

 unquestionable evidence of shallow water and even mud-flat 

 origin, cannot fail to strike with astonishment the student of 

 the physical history of the Trias. Yet, after long study of 

 this formation, and a residence of many years within its 

 borders, we cannot arrive at any other conclusion. The only 

 escape seems to he found in the possible existence of faults 

 and displacements, as yet unrecognized. 



Prof. Rogers* accounts for the accumulation of these beds of 

 red sandstone and shale, and also for their inclined position, 

 by assuming the existence, in the Triassic period, of a great 

 river which, rising in ISTorth Carolina or Georgia and flow- 

 ing northward, emptied into the ocean near the present 

 mouth of the Raritan, in New Jersey. Prof. Rogers holds 

 that the sediment forming the Triassic beds was brought 

 by this river and deposited in its present inclined position, dip- 

 ping, as we have seen, at an average angle of 10 or 15 degrees, 

 but in some cases much more inclined. Such a supposition 

 appears to us entirely contrary to the almost universal mode of 

 deposition, which, especially for any considerable area, is 

 always approximately horizontal. The thin even bedding of 

 many of the layers of soft shale, which are frequently continu- 



* The views advanced by Prof Eogers (Final Keport Geol. of N. J., 

 1840, pp. 163-171) are quoted in full by Prof. Mather in his report on the 

 geology of the southern portion of New York (Geology of N. Y., Part 1, pp. 

 289 — 293.) He agrees with Prof. Eogers in the main, but ascribes the depo- 

 sition of the Triassic beds to the meeting of equatorial and polar oceanic 

 currents: see page 192 of his report. 



Prof. Eogers's theory is dissented from by Elisha Mitchell, in his book 

 entitled " Elements of Geology, with an outline of the geology of North Caro- 

 lina," p. 133. 



