60 
RELATIONS OF THE TACONIC SYSTEM, 
The section in the margin exhibits the con¬ 
nection of the quartz and primary schists, with 
which, however, there are beds of granite 
containing a peculiar blue quartz, that enters 
also into the composition of the breccia already 
referred to ; and I may add that I observed 
a. Brown sandstone or granular quartz ; b. Gneiss with beds of gra¬ 
nite, in which quartz predominates ; c. Thick beds of drift. tlllS clt AdcllTlS (MciSSclchuSGtts) 5 IlCcirly forty 
miles further south. 
I have now stated the facts in regard to the junction of the Taconic system, first, on the 
west with the New-York or Silurian system; and secondly, on the east with the Primary 
schists, with which it is also unconformable. From the preceding account, it is not to be 
doubted but that there is a system of rocks lying, as has been heretofore maintained, 
between Hoosic mountain range and the Hudson river, of an age posterior to the gneiss 
and mica slate, and anterior to the New-York system. It consists, throughout all its beds, 
of sedimentary matter generally in a state of fine division. These beds are conformable 
to each other, and arranged in uninterrupted succession, although their lithological charac¬ 
ters are very diverse. 
These facts, therefore, go to show the unity of the rocks which compose the Taconic 
system; being deposited during a greatly extended period, which will be shown to have 
abounded in part in organic bodies, whose forms were as remarkable as any in the animal 
kingdom. 
From considerations which have been adduced in this section, the doctrine of metamor¬ 
phism is of no consequence. We may admit the fact, without involving the question of 
age, either in one or both systems : each may have undergone great changes in mechanical 
texture, without embarrassing our conclusions, even though two limestones, slates or sand¬ 
stones become by those changes identical in lithological features or composition. 
I have already stated that the Taconic system lies between the Hoosic mountain range 
on the east, and Hudson river on the west: I may now add that it embraces a belt of country 
at least forty miles wide. This statement is confirmed by my researches since the Report 
on the Second District was published, its extent being increased by an extension of the 
Taconic slate beyond those limits which I had then fixed upon. In this ancient system, 
contrary to what would be expected, perhaps, we find as few disturbances as during any 
other subsequent periods ; that is, in the belt of country between the Hudson at Albany and 
the Hoosic mountain, no remarkable ones seem to have occurred, except that by which 
the rocks have been thrown into an inclined position : there are no intrusions of igneous 
rocks, as dykes, beds of granite, etc.; though when we trace the system south, distur¬ 
bances are quite common; but even in the midst of them, I may say that the metamor- 
phisms are no greater than in many rocks of a much later date. So that the effects of 
intruded igneous rocks are not always strongly manifested; and, in fact, in New-York, 
they are scarcely worthy of attention, unless indeed for the very point stated, the extremely 
slight change that appears just at the junction of the two rocks, and then the alteration 
