101 DERANGEMENTS OF THE TACONIC SYSTEM. 



it" they have been exposed to what is termed diluvial an ion, and patches have been worn 



or cut through, showing the lower racks in tin- same strike. Now in a system as old as 

 the Taconic, we must admit its great Liability to be deranged, and its members to be 

 changed in various ways ; in ways aa numerous as the physical agents themselves, fire, 

 water, frost, abrasions, disintegration, etc. Ii is therefore reallj to be expected that diffi- 

 culties should ocour in the adjustment of its members; but these by no means appear 

 insurmountable, when we are once in possession of all the facts relating to the system. 



The doctrine which I wish to inculcate in the preceding remarks, is, that a system of 

 rocks may be rendered obscure by a parallel division of its beds, or by a parallel separa- 

 tion of it-- individual members : they may be so divided as to he wom out by the agents or 

 pov. ture, or become insignificant, or separated so far asunder as to be lost sight of ; 



and the older any system is, tlic more liable is it to suffer by these accidents. The Taconic 

 system has especially suffered by these causes ; and in consequence of its proximity to other 

 ins and rocks probably of a similar origin, many perplexing questions arise, of which 

 other Bystems are entirely free. 



In studying the rock- of this nr any oilier system, I select those districts where there is 

 the least disturbance. By this course, I am enabled to learn, not only what the members 

 of tlie Bystem are, l>ut also their true order of succession. In this system, I have particu- 

 larly examined the district marked out at the head of this article, .as it is here that few if 

 any intrusive rocks of any kind occur; and I find a certain number of them King in 

 parallel bands, which on both side-, the east and west, prove unconformable to the two 

 Bystems lying one above the eastern Bystem of Bchists, and the other below the shales that 

 constitute a part of the western Bystem, the New-York or Silurian. 



Now wherever I find these members, although they may be separated from each other 

 as they are at the Highlands, I am determined still to call them by their right names; 

 though I am ready to express my fears that some of my favorite bantlings have been so 

 much altered in some localities, that I may fail to recognize them. I suspect, too, that it 

 may happen in some cases that only the fragments of the Bystem have come down to us, 

 so that it will be impossible to bring together the remnants in such a condition as to make 

 even a tolerable appearance on a map. 



I have only a few more words to say in this connection, namely, that the difficulties 

 attending the adjustment of the rocks of the Taconic bj Btem cannot be appreciated without 

 a tolerable knowledge of the characters of all the rocks with which they lie in juxtaposi- 

 tion. Very little embarrassment is occasioned b\ the presence "f gneiss or mica slate near 

 any of the members of the New-York system, so far at least as to distinguish one from 

 the other ; but not so with the rocks under consideration, for reasons which I have already 

 given. 



