242 The Taconic Question Restated. [March 
in his “ Manual of Geology” in 1860, and in his subsequent re- 
ports on the geology of North Carolina. 
§ 19. It is important to note that the line of demarcation 
between the Lower and Upper Taconic series corresponds to the 
stratigraphical break already pointed out, in 1832, by Eaton be- 
tween the Transition Argillite and the First Graywacke. It 
should be further mentioned that this division is one between a 
series of essentially crystalline strata below and one of earthy 
sediments above ; and, moreover, that the facts known with regard | 
to the distribution of the two show clearly that their areas are not 
co-extensive. While found superimposed upon the Lower Ta- 
conic in certain districts, the Upper Taconic is wanting over 
great areas of the Lower, and is elsewhere seen in many places 
resting unconformably upon pre-Taconian crystalline schists. 
It was this Upper Taconic which Emmons, in 1842, declared 
to belong to “the lower part of the Silurian system,” which he 
showed, in 1844, to contain organic remains, such as trilobites 
and graptolites, in several of its subdivisions of shales and 
sandstones, remarking that while they had not yet been found in 
the Sparry Lime-rock sufficient search had not been made therein. 
It was the same Upper Taconic or Taconic slate group which he 
later, in 1860, declared to correspond to the Primordial zone of 
Barrande, which latter was included alike by Barrande and by the 
other followers of Murchison, both in Europe and America, in 
the so-called Silurian system. Yet, notwithstanding all these 
facts, we find that the discovery in Eastern New York of fossils 
of Cambrian and Ordovician age in what J. D. Dana calls “a 
limestone of the original Taconic of Professor Emmons,—his 
Sparry Limestone,’—is brought forward in 1885 as an argument 
against the views of Emmons. Ina letter to Marcou, dated Al- 
bany, September 1, 1860, Emmons writes, “ The upper part of the 
Taconic is equivalent to Barrande’s Primordial group,” while in 
his “ Manual of Geology,” also published in 1860, he declares (p. 
: that “it has been shown that the Primordial zone in Bohemia 
in co-ordination with the upper series of the Taconic rocks.” 
tn another letter to Marcou, in November of that year, he ex- 
pressed the opinion that neither his Taconic system nor the Pri- 
mordial zone or group of Barrande was Silurian, but in a subse- 
quent letter, November 29, 1860, admits his misconception and 
writes, “ On reading his [Barrande’s] papers I found that, after all, 
