240 3 The Taconic Question Restated. [March 
same geographical distribution and similar lithological characters, 
had long before been described by Eaton as resting unconform- 
ably upon the Transition Argillite (§ 2), and subsequently by 
Mather (§ 8) and (apparently) by Emmons (§ 10) had been referred 
to the horizon of the Second Graywacke. It will also be re- 
membered that the Sparry Lime-rock, which we know forms an 
upper member of this Graywacke series, was already by Eaton, 
in 1832, regarded as the stratigraphical equivalent in the eastern 
region of what he had called the Calciferous Sand-rock to the west 
of Lake Champlain. Emmons had thus in 1846, after his pre- 
vious statements printed in 1842 and 1844, arrived to the same 
conclusion as his old master, and now assigned the great mass 
of uncrystalline more or less fossiliferous strata, which he subse- 
quently called Upper Taconic, to a horizon below the Trenton 
limestone, and regarded it as the equivalent of the Calciferous 
Sand-rock, including, however, as he afterwards taught, also the 
representative of the Potsdam sandstone. When he speaks of 
this great Graywacke group as resting on Taconic slates, we 
“must remember that already in his first recognition of the ae 
position of Calciferous Sand-rock to Taconic slates in 1844, a 
above cited, he had declared these to be “ probably the Mag- 
nesian slates,’ which correspond to the Transition Argillite of 
Eaton, included in the Lower Taconic, and not to what he else- 
where designates as the proper “Taconic Slate” group, which 
was later included in his Upper Taconic, and-is no other than 
this same “ protean” Calciferous Sand-rock and Potsdam sand- 
stone, or the First Graywacke itself. 
17. Emmons could scarcely have defined more clearly than 
he did in 1844* the great extent and the boundaries of this 
Taconic slate group as then known to him, with its breadth of 
fifteen or twenty miles, occupying the greater part of the three 
counties named in Eastern New York, and stretching from north 
to south one hundred and fifty or two hundred miles; its limita- 
tions on the west by the overlapping upper shecahers: of the 
Champlain division, and on the east by the great mass of the 
Sparry limestone, portions of which are said to occur at intervals 
in the section farther westward. He, moreover, declares in 1844, 
* Agriculture of New York, i. 65-72. We quote from this volume for the reason 
dita thai. tine fiat ind separater ceinied elimina ab esd 
4] á 
pi x F 
