130 DR. THOMAS STEEEY HUNT ON THE 



the addition of the Oneida sandstone. The study of its fossils by Billings now led Logan 

 to see that its position was really below and not above the Trenton limestone; but instead 

 of adopting Emmons' name of Upper Taconic, he gave to the series, as seen near Quebec, 

 the name of the Quebec group, then described by Logan as a stratigraphical equivalent of 

 the Calciferous sand-rock. Taking as a type the well-known section there displayed upon 

 the St. Lawrence, he called the apparently superposed sandstone the Sillery, and the 

 underlying fossiliferous limestones and shales (the Sparry lime-rock of Eaton,) the Levis 

 division. This was a reversal of the order described by former observers, and there can 

 be no doubt that the section at Quebec is really an inverted one, the Sillery sandstone 

 being the oldest and not the youngest member of the series as there displayed. This his- 

 tory has already been given at length in Chapter VI of this essay. 



§ 150. We have there also explained how Logan's view of the position of the Sillery 

 sandstone was made to support the notion that the crystalline schists which have been 

 found to underlie it were the altered representatives of the sedimentary strata found be- 

 tween the Sillery and the Levis, which he had called the Lauzon division. Following 

 the rocks of his Quebec group southward into Vermont until he met the grauvilar marbles, 

 of the Lower Taconic, Logan was led to include these also in the Quebec groiip, and to re- 

 gard them as the Levis limestone in an altered condition. This, as already set forth in 

 §§ 115-116, is seen in his large geological map of Canada and the Northern States, pub- 

 lished in 1866, after he had spent some time in tracing these rocks through western Ver- 

 mont and Massachusetts into eastern New York. Therein the Lower Taconic limestone 

 in Massachusetts is represented as an uninterrupted continuation of the Levis limestone- 

 from the province of Quebec, brought up along an anticlinal, and having on both sides 

 overlying it, successively, the Lauzon and Sillery divisions, — these, on the west side of 

 the anticlinal, having the ordinary type of the uncrystalline First G-reywacke or Upper 

 Taconic, but being represented on the east side by the crystalline schists of the Green 

 Mountain range, their supposed equivalents. Few will now question that Logan was 

 wrong in this latter point, or will doubt the greater antiquity of these crystalline rocks. 

 On the other hand it is to be noted that, in thus asserting the infraposition of- the Lower 

 Taconic marbles to the First Grraywacke or Upper Taconic series, Logan but confirmed the 

 older observations of Eaton and Emmons, and only erred in having, by a false interpréta, 

 tion of the succession of the latter series near Quebec, assigned the Levis limestone to its 

 base, by which he was led to confound it with the Lower Taconic limestone. In either 

 view, he placed the latter below the series of several thousand feet of sandstones, conglom- 

 erates and shales, which constitute the First Grraywacke of Eaton and the Upper Taconio 

 of Emmons. 



§ 151. We have already seen that Emmons, as early as 1846, had recognized the fossil- 

 iferous character of the First Grraywacke, which he afterwards called Upper Taconic ; that 

 he described and figured, in 1855, trilobitic forms found therein, and did not hesitate, in 

 1861, to declare that it corresponded with the Primordial zone of Barrande." Thus it hap- 

 pened that Barrande, Marcou, and after him Perry assumed the Taconic system to be the 

 equivalent of the Primordial zone or Cambrian of Great Britain, Bohemia and Spain, — they 

 having failed to recognize the distinction which Emmons had made between the Lower 



* See, in this connection, Barrande and Marcou on tlie Primordial Fauna and the Taconic System; Proc. Bos- 

 ton Soc. Nat. Hist., Dec, 1860, vol. vii, pp. 309-382. 



