1846.] The Taconic System. 207 



low leA'el, even below the level of the adjacent country, uncovered 

 by diluvial action. We find also the rocks preserving the same re- 

 lative position, and moved but little from that in which they were 

 originally deposited. Where movements have taken place at or 

 near the junction of the two systems, it has been, as stated above, 

 a simple uplift, and not an overturning in the mode maintained 

 by the Profs. Rogers. If such was the true view of the case, 

 either the Potsdam sandstone or the calciferous sandstone would 

 be the superior mass, and the Trenton limestone and its slate the 

 inferior. This position is never found to prevail. 



Again, when the calciferous sandstone reposes on the Taconic 

 slate, and the line of junction exposed, the phenomena presented 

 prove the calciferous sandstone to have been a rock succeeding to 

 the Taconic slate. The brecciated mass of slate and a little 

 limestone prove this, and the inclosed masses of slate testify to its 

 anterior existence to the limestone. It is by observations of this 

 kind that w^e have established the succession. So the existence 

 of masses of a sedimentary limestone at the top of the Potsdam at 

 Chazy, prove the prior existence of the rock when the Potsdam 

 was being formed. These are all elementary facts, which we 

 should not be at the trouble to state, were it not that our views 

 have been regarded as unsound and untenable. We have had 

 occasion to regret, that superficial examinations only have been 

 made by those who have made the strongest assertions; that some 

 have been wedded to a theory or a nomenclature, which, if the 

 Taconic system is received, must require very important modifica- 

 tions in order to be received, or be at all applicable to our rocks. 

 If the Taconic rocks are but lower members of the New York 

 system, how happens it that not a molusk or conchifer has been 

 found in them, inasmuch as the New York rocks abound in them 

 to a remarkable extent. This very fact should have led geolo- 

 gists to suspect the truth of the view; for notwitstandino- their 

 age and the disturbances to which they have been subjected, they 

 contain fossils of a delicate kind, and hence it cannot be said that 

 they are destroyed by metamorphosis. 



