206 The Taconic System. [Oct., 



position; but taking the thin beds of limestone which contain the 

 fossils of the limestones at well known localities as way boards, 

 and a great part of the difficulty in regard to the Taconic system 

 is removed. Superposition and succession was considered, as the 

 main facts upon which the doctrines supporting the Taconic sys- 

 tem rest, yet it was farther maintained that the fossils of this sys- 

 tem are all different from the New York; and what is quite re- 

 markable, no molusk or conchifer has yet been found in it, not- 

 withstanding it has been examined more carefully than any other 

 series of rocks in this country. 



Conformity of position in the masses between the Hoosick 

 mountain and the Hudson river was considered sufficient evidence 

 to prove that they all belong to one series. Those who maintain 

 that they are merely altered rocks of the Champlain division, 

 admit of course the unity of the masses as it regards the period of 

 their formation. The superimposed rocks of this division are 

 ( xcepted. They appear in insulated fields, and may be distin- 

 guished from the rocks of the Taconic system by their lithological 

 characters, or the want of conformity to the latter." 



To the above we desire to add a few remarks in consideration 

 of the importance of the subject in a geological point of view. 

 What was said on the occasion was designed merely as a state- 

 ment of those facts which go to prove directly the existence of 

 the rocks as an independent system. The most important fact is, 

 as has been stated, the relative position of the two systems; and 

 it is now uncontradicted, that in numerous places the New York 

 system, or its lowest members, are superimposed upon the Taconic. 

 This being the case, unless it can be shown that there is an over- 

 turning of the strata in such a manner as to produce an entirely 

 inverted position, the system must stand. Observation, however, 

 in no case favors this view of the question, inasmuch as where 

 two members of the New York system exist together, they pre- 

 serve the position in which they were deposited, and the only 

 change they seem to have suffered is simply an elevation by a 

 force acting beneath the Taconic slate, by which the whole is 

 raised above the surrounding country. We find these rocks at a 



