1887] The Taconic Question Restated. 313 
which has been altered. When, subsequently, Logan traced the 
great Graywacke belt of Eaton southwestward into Vermont, and 
along the western base of the Taconic Hills to the Highlands of 
the Hudson, recognizing its identity with his Quebec group, and 
finding it, in its southward extension, to rest in many parts on 
the crystalline limestones of the Lower Taconic (the Primitive 
Lime-rock), he declared these to be the altered representatives 
of the Levis or Sparry Lime-rock, made by him the lowest 
division of the same Quebec group; the Lauzon, according to 
his hypothesis, while nearly four thousand feet in the vicinity of 
the city of Quebec, being elsewhere reduced to a very thin layer, 
or entirely wanting. 
§ 30. That the great crystalline series which forms the Lower 
Taconic of Emmons lies, as maintained by Eaton, beneath the 
horizon of the First Graywacke, from which it is separated by a 
stratigraphical discordance, is thus confirmed by Logan, as well 
as by J. erry, who, in 1867, described the Lower Taconic as 
Sai of quartzites, marbles, and talcose schists; and, later, 
by Marcou, who also notes the want of conformity between the 
Lower and Upper Taconic. That the horizon of the Lower 
Taconic is in fact below that of the First Graywacke is disputed 
by no one who has ever studied the region in question, and the 
` only ground on which it can be assigned to a higher horizon is 
by maintaining the old error of Mather, who conjectured this 
First Graywacke or Upper Taconic to be newer instead of older 
than the Trenton limestone,—a mistake now recognized by all 
who have investigated this Graywacke belt. 
We have elsewhere pointed out the grounds on which those 
who followed the erroneous view of Mather as to the horizon of 
the First Graywacke regarded the Lower Taconic quartzites and 
limestones as Trenton or post-Trenton in age. C. B. Adams and 
W. B. Rogers regarded the Red Sand-rock and its associated 
limestones near Burlington, Vermont, which are included in the 
First Graywacke, as of Medina (or Medina and Clinton) age. Fol- 
lowing this, Adams maintained, in 1846, that the quartzites and 
crystalline limestones of the Lower Taconic were but the altered 
equivalents of this First Graywacke, and Rogers proclaimed, in 
1851, that these crystalline limestones are “ probably Upper 
Silurian or Devonian,” while Edward Hitchcock, in 1861, con- 
ceived that they “ may be as recent as the Carboniferous rocks.” 
