J. D. Dana— Views of Professor Hmmons. 415 
yond) with “contradictions” and “ perplexing discrepancies ” in 
his volume of 1842; and in a note at the bottom of the page, 
“pages 121, 124, 125, 280-282, and further, p. 147,;” are referred to 
for testimony on this point. Only one of these pages is in the 
chapter on the Taconic system—the “and further p. 147.” I find 
no “contradictions ” or ‘‘ perplexing discrepancies ” in that chap- 
ter, or in anything relating to the Taconic system. 
Professor Emmons does not merit the condemnation thus made; 
for he is clear and consistent throughout. 
As to the change of opinion asserted, I find, as I had done be- 
fore, that in 1842, Professor Emmons, contrary to the idea con- 
veyed on page 123 of the paper in the Naturalist, made the Sparry 
or western limestone older than the Stockbridge limestone, be- 
cause the western dipped eastward beneath it; he commences his 
paragraph on the subject of relative age (Rep. Geol. N. Y., “and 
further, p. 147,”) with the sentence “there seems to be no valid 
reason against the opinion that the most western belt of lime- 
stone is, after all, the oldest of the Taconic limestones.” 
In 1844, 1846, speaking, in his Memoir, of the Taconic rocks, he 
says, p. 63 of the Agricultural Report and 19 of the 1844 pamph- 
let): “I shall describe the rocks in the descending order,” and 
this is the order: 
First. “The Brack State” (on pp. 63-65), described as af- 
fording at Bald Mountain, Trilobites. 
Second: “The Taconic SLATE WITH ITS SUBORDINATE BEDS ” 
(on pp. 65-72); of which he says: “ Occupies almost the whole 
of Columbia, Rensselaer and Washington Counties” (p. 72); 
“extends from Lansingburgh to the Sparry limestone in the 
eastern part of Hoosic near the western bounds of Bennington in 
Vermont—at least 20 miles in a direct line” (p. 72); ‘“ It crosses 
the [Hudson] river near Poughkeepsie, ranging southward so as 
to underlie the belt of country to the west of Newburgh for six 
or eight miles” (p. 103). In these and other statements he gives 
the Taconic slate a wide range, and includes under it slates near 
Poughkeepsie that in recent years have afforded Hudson River 
brachiopods. He makes it older than the Black Slate. 
Third: The “ SpARRY LIMESTONE (on pp. 72-74): of which he 
says, ‘‘Occupies the belt of country comprising the eastern part 
of Dutchess, Columbia, Rensselaer and Washington counties (p. 
73); ‘“‘not far west of the dividing line between Massachusetts, 
Vermont [on the east side] and New York [on the west |” (p. 74) ; 
“through Ancram, Hillsdale, Canaan, New Lebanon, Berlin, 
Petersburgh, Hoosic, Whitecreek,” etc. (p. 74). In the account 
of this limestone I find nowhere, any more than in that of the 
Taconic slate, the slightest intimation of a change in his opinion 
as to its age: All the rocks of the Taconic series are made un- 
equivocally older than the Potsdam sandstone. 
As above indicated, Professor Emmons did make one change in 
1844, and a wise one. In 1842 he argued from the eastward dip, 
as I have shown, that the Sparry limestone was the oldest of the 
