136 
GEOLOGY OF THE SECOND DISTRICT. 
and where all the relations of the lower masses can be observed. To leave, therefore, a group 
or system of rocks which belong evidently to a position between the primary of the Atlantic 
ranges of mountains, and the New-York system, would 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 which 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. 
The 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, m 
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 who 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 for his scientific attainments, gave an elaborate essay, wherein the rocks 
were described as fully 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 published, 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 publications, 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. 
