TACONIC QUESTION IN GEOLOGY, 133 



rock of Eaton — followed to the east by two other belts, difFeriug- from the first in lith- 

 ological characters, and constituting the Granular lime-rock of Eaton. Emmons then pro- 

 ceeds to inquire whether these three may not be one and the same bed repeated, or, in 

 case there should be two or more distinct beds, which belt is the oldest. " It is," he says, 

 "a question whether these three several belts of limestone may not belong to one bed ; it 

 is at least worthy of attentive examination. It is, however, a question that 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," etc. It had been customary, he tells us, to look upon the most easterly belt 

 as the oldest, and that at the western base of the Taconic range as the newest, notwith- 

 standing the fact that the most westerly belt seems to dip beneath the eastern. At the 

 same time he remarks that, in the absence of fossils, " we must judge of their age by their 

 relative position, or by superposition, and, so long as the most western belt, by this rule, 

 is the inferior one, I can see no necessity in the case to suppose a series of complicated 

 changes, in order to make it coincide with our conjectures." '" 



§ 161. A careful perusal of the page from which these extracts are taken, and, indeed, 

 of the citations themselves, suffices to show that Emmons was at that time — 1842 — in 

 doubt which of these limestones should be regarded as older and which younger, or, in- 

 deed, whether they were not all repetitions of the same belt. These doubts were, how- 

 ever, resolved by him, and those familiar with his subseq^^ent studies and publications are 

 well aware that he soon afterward saw reason to follow Eaton in assigning the Sparry 

 lime-rock of the western belt to the summit of the great Greywacke or Upper Taconic 

 series, which he showed to be fossiliferous and Cambrian in age. The whole history of 

 this is before the world in Emmons' later publications of 1846, 18.55 and 1860, but of this, 

 in 1882, Dana tells us nothing, and, after asserting that the Taconic rocks constitute one 

 conformable series— which, so far as regards the Lower Taconic, has never been cjuestioned 

 — refers to the well-known fact that the limestones of the western belt described by Em- 

 mons, have since yielded not only a Cambrian, but an Ordovician fauna, and then, falling 

 back on the words of Emmons in 1842, already cited, declares that "if Professor Emmons' 

 view is right with regard to the western and eastern limestones and the intermediate Ta- 

 conic schists, namely, that the order of superposition is the order of age, then the western 

 is the oldest of the three ;" but, " inasmuch as the western limestone is partly of Trenton 

 age, it makes the eastern limestone younger still, or, a part of the Hudson River group." '^ 

 Dana, however, adds that he accepts the alternative conjecture of Emmons in 1842, — which 

 he assumes to be established, — that the eastern and western limestone belts in question are 

 but repetitions of one and the same stratum, and thence argues that the granular marbles 

 of the Taconic range are altered lower paleozoic limestone. 



§ 162. The different views with regard to the geological horizon of the Lower Taconic 

 or Stockbridge limestones of Emmons — the Granular lime-rock of Eaton — may be resumed 

 as follows : — 



I. That they are pre-Cambrian, and occupy a position below the Potsdam sandstone 

 or Red Sand-rock, and the Quebec group of Logan, which together constitute the First or 



'" Emmons, Geology of the Northern District of New York, p. 147. 

 " Quar. Geol. Journal, xxxviii, 465. 



