TA^CONIC SYSTEM. 
147 
still farther east across the valley of the Hoosic in Williamstown, Mass,, to the foot of Saddle 
mountain, there is another; and again at the base of the Hoosic mountain is another still, which 
is the most easterly of all. Now it is a question whether these several belts of limestone 
may not belong to one bed ; it is at least worthy of attentive examination. It is, however, a 
question which I have often sought to solve, but I have not yet succeeded in a way which is 
satisfactory to my mind ; but I have concluded to regard them as distinct, inasmuch as there 
are differences of some importance, particularly in thickness, and a want of correspondence 
in the beds themselves. There appear to be at least three distinct ranges : 1st, The belt at 
the foot of the Hoosic mountain; 2d, The one at the base of Saddle mountain, and which 
spreads through the valley of Williamstown; and 3d, The belt at the western base of the 
Taconic range. These belts appear to pursue nearly parallel courses, and never to com¬ 
mingle. 
There is still another vexatious question; it is in relation to age. It has been customary 
to regard the limestone along the base of Hoosic mountain, or the most easterly belt, as the 
oldest; and that at the western base of the Taconic range, the newest. Viewing them in 
this light, we are perplexed at once in consequence of their dip ; for the most westerly dip, 
as has been repeatedly observed, beneath the most easterly, or that which has been considered 
the oldest mass. Now if questions of this kind are to be settled by appearances, that is, by 
coarseness of grain or texture, or by what we deem primary aspect, then perhaps the deci¬ 
sion is right; but I do not know that we have any right to this assumption. The primary 
aspect is sometimes borne by rocks of modern origin; and in neither case can we decide the 
question by proximity to any other system, that is, we have little reason for saying, that be¬ 
cause the eastern belt lies along the primary, it must therefore be older than the western, 
which lies along the fossiliferous rocks of the New-York system. The truth is, we do not 
know "the position of the basin in which these rocks were deposited, to enable us to decide 
at this late day which is the older, or which the newer side of the basin, except it be from 
the dip of the rocks. There seems to be no valid reason against the opinion that the most 
western belt of limestone is, after all, the oldest of the Taconic limestones. All being desti¬ 
tute of 'fossils, we must judge of age by their relative position, or by superposition ; and so 
long as the most western belt by this rule is the inferior limestone, I can see no necessity in 
the case 'to suppose a series of complicated changes in order to make it coincide with our 
conjectures. 
If we direct our attention 'for a moment to the views of other geologists, particularly to 
those entertained by Profs. Hitchcock and Rodgers, the reader will be able to compare both 
with his own observations. Viewing, as these gentlemen do, the Taconic rocks as metamor- 
phic, and as really an eastern prolongation of the members of the Champlain group, their 
peculiar dip, together with their other relations, are explained on the supposition of their 
‘being thrown into a series of folds or plications by lateral pressure, each fold producing an 
elevated range of rocks or mountain ridges, with a steepness much greater on the side most 
distant from the great mass of primary, than upon the side towards it. The curvatures or 
plications, together with the varied steepness, is represented in the following figure : 
