136 GEOLOGY OF THE SECOND DISTRICT. 



and wlicre all the relations of the lower masses can be observed. To leave, therefore, a group 

 or systent of rocks which belong evidently to a position between the primary of the Atlantic 

 ranges of mountains, and the New- York system, woukl have left a chasm unfilled, a work 

 incomplete in itself. In these remarks, the writer does not expect to be able to give full jus- 

 tice to the subject on whicli he is about entering ; the merit, to a certain extent, of removing 

 some of the obscurities which envelope this system of rocks, is all that he would claim, 

 together with the fact of having placed it in a new light before the American public. 



Tlie Taconic system, as its name is intended to indicate, lies along both sides of the Taconic 

 range of mountains, whose direction is nearly north and south, or for a great distance parallel 

 with the boundary line between the States of New-York, Connecticut, Massachusetts and Ver- 

 mont. The counties through which the Taconic rocks pass, are Westchester, Columbia, Rens- 

 selaer and Washington ; and after passing out of the State, they are found stretching through 

 the whole length of Vermont, and into Canada as far north as Quebec. It is, however, in 

 Massachusetts, in the county of Berkshire, that we find the most satisfactory exhibition of 

 these rocks. They form a belt whose width is not far from fifteen miles along the whole 

 western border, and which extends clearly to the western base of the Taconic range. The 

 greatest breadth, therefore, as will be seen by an inspection of any map of this section of 

 country, is wider upon the eastern than upon the western side of this range. In Vermont, 

 they range along the upper members of the Champlain group, and thus become connected 

 with the Second district. 



Persons ivho have contributed to our knowledge of the Taconic rocks. 



By reference to the early numbers of the Journal of Science, it will be seen that Profs. 

 Dewey and Hitchcock early turned their attention to the rocks under consideration. The 

 former, distinguished fir his scientific attainments, gave an elaborate essay, wherein the rocks 

 were described as fuHv as was possible in the infancy of geology in this country ; in fact, so 

 far as mere description is concerned, very little remains to be added. 



In 1829, the History of Berkshire was pubhshed, the matter of which was contributed by 

 the clergymen of the several parishes in the county. In this work an abridgment of Prof. 

 Dewey's former essay appeared, so that a general account of these rocks has been widely 

 circulated. Prof. Hitchcock has at various times furnished many important facts in regard to 

 the geology of Berkshire, but, as appears from his pubhcations, has relied mainly upon the 

 information derived from Prof. Dewey's labors, especially in his elaborate and excellent work 

 on the rocks of Massachusetts. To these gentlemen, therefore, we are principally indebted 

 for the facts which have been placed before the public. 



It will be observed, however, that it is many years since those publications were made, or 

 rather since the observations were made which form the basis of all the accounts which have 

 appeared. We have then an additional reason for making a reexamination of the masses 

 which compose this system of rocks ; for it is to be expected that an application of the prin- 

 ciples of geology as now established, will somewhat modify our views in relation to them. 



