TACONIC SYSTEM. 135 



CHAPTER VII. 



TACONIC SYSTEM. 



It has been deemed advisable to annex to the general account of the group of rocks of the 

 northern district, a brief sketch of the series which constitute the Taco?iic System. By refe- 

 rence to the preceding pages, it will be perceived that they do not appear in the Second Geo- 

 logical District ; but inasmuch as some of the most important and interesting relations of the 

 Champlain group could not be understood without a knowledge of this series, I propose to 

 describe them in this place. This determination is, however, in accordance with my original 

 design, viz. to furnish a full account of the rocks up to the grey sandstone, the highest and 

 last member in the Chainplain group. In taxing myself thus, I have been influenced by 

 the desire to furnish the materials necessary for a complete work on the New- York rocks, as 

 far as my district, and its connection with those adjacent, is concerned ; and to make this 

 volume as distinct from, and independent of, the reports of the other districts, as the nature 

 of the subject and its relations would permit. The fulfilment of this task requires the work 

 which I have now undertaken. 



These remarks are made in part as a general apology for stepping over the bounds of the 

 Second district, and out of the limits of the field which was originally assigned me ; and par- 

 ticularly to the geologist of the First district, within whose bounds this system of rocks is 

 fully developed. But that the propriety of this course may be more clearly understood, I 

 remark farther, that it is only in the Second district that the lower members of the New-\ ork 

 system are fully developed. In the First, they are much disturbed, and the relations are 

 obscure ; in the Third, which extends to the primary north of the Mohawk valley, there are 

 several members wanting, and some whose character, if taken alone, are insufficient to entitle 

 them to the appellation of distinct masses ; while in the Fourth district, the series commences 

 with the Medina sandstone. It will be perceived, therefore, that my design is to fiirnish a 

 full account of the rocks which are in any way connected or related to the lowest group of 

 the New- York system ; and as the materials or facts are derived both from a series which are 

 undisturbed and those which are dislocated, and as I have reason to suppose also are more 

 complete than in any other portion of the State or Union, they must form the only basis of a 

 satisfactory description, as it is the only field where all the members are distinctly developed, 



