OF THE TACONIC ROCKS. 63 



ra/ists. It is not my purpose here, however, to pursue the theory of these changes. I 

 regard the dips as having been produced by simple uplifts of the strata; not indeed that 

 they have not been subjected to lateral pressure, by which curvatures were produced in 

 many instances. But admitting the Rogerian theory as it regards foldings and southeasterly 

 dips, and giving it all the stretch of faith which confidence in sound geological principles 

 will admit, still that part of it which connects the Hudson river shales with the Taconic 

 slates in prolonged arches must necessarily fall to the ground. 



The position and order of the Taconic rocks I have exhibited in the section Fig. 7. It 

 shows the regular parallel southeasterly dip, and the principal beds together with the suc- 

 cession. From this the reader or student will understand what was adverted to by the 

 terms inverted strata. Thus the numbers 5, 6, 7 and 8 refer to the Taconic slate in its sub- 

 ordinate beds, which, as they dip in the diagram, would pass necessarily beneath the rocks 

 situated towards A. 



Fig. 7. 



A. Primary schists. 1. Granular quartz, or brown and white sandstone. 2, 2. Stockbridge limestone. 

 3, 3. Magnesian slate. 4. Sparry limestone. 5. Taconic slate. 6. Roofing slate. 7. Rough 

 coarse siliceous beds. 8. Flinty slate. 9. Hudson river shales. 



§ 2. Black slate. 



Reasons why this rock is separated from the Taconic slate. First discovery of Crustaceans in this mass. 



Characters as a rock obscure. Its fossils. 



I shall describe the rocks in the descending order ; and by so doing, I commence with a 

 mass, of which there is some doubt whether it ought to be considered a distinct rock, or 

 merely the upper portion of the Taconic slate ; still I am disposed to regard it now as a 

 separate and distinct rock, forming, so far as examinations have been made, the highest 

 member of the Taconic system. The circumstances which have led to the separation of 

 this from the rock referred to, are of an interesting character ; interesting particularly as 

 being connected with the discovery of crustaceans where they were least expected. While 

 examining the strata near Bald mountain, during the early part of September of the 

 present year, my attention was arrested by the discovery of the fossil figured in Plate II. 

 fig. 3, which resembles very closely an annelide of the scolopendrian family ; but the 

 specimen is imperfect, and hence its true character cannot be determined with certainty. 

 This discovery led to farther search for additional specimens, but no other fragment has 

 yet been found ; although in the course of different searches, two distinct species of trilobites 

 were found by my friend Dr. Fitch, and fragments of others too imperfect to describe. 



