J. D. Dana—Taconic Rocks and Stratigraphy. 271 
ten incorrectly, I add here that Haton gives credit for what he 
knows of the region to Dewey.* 
But Prof. Dewey’s work was only a beginning. Prof. 
Emmons took up the investigation thus initiated and made 
thorough work of it; and finally, adding to his study of the 
Williamstown region that of western Berkshire and Hastern 
New York, gathered the facts upon which he based the ‘Taconic 
system, and his opinions as to the contrast between them and the 
oldest Paleozoic strata of central and northern New York. 
2. General features.—The general trend of the chief Taconic 
Range and of the Taconic belt of rocks is very nearly that of the 
western New England boundary—or about N. 15° H. along the 
limit of Massachusetts, and about N. 5° E. along that of Ver- 
mont. 5 
The topography of the part under consideration is similar to 
that of the more southern section already described. The lime- 
stone is intersected from north to south by ridges of schist and 
the other overlying rocks, and the most of these schist ridges 
stand isolated within the limestone area, or run out into the 
area from the larger ridges like peninsulas. Few limestone 
areas on the map are wholly enclosed by the schist, and thus 
detached from the main mass. 
3. The old subdivision of the Taconic limestone into an eastern and 
western belt not valid.—The distinction of two ranges or belts of 
limestone, an easlern, east of the main Taconic Range, and a 
western, west of it, was first recognized by Dewey, who named 
them, in the language of the day, the Primitive and the Transi- 
tion, the latter name being given to the western, because the 
rock was but feebly crystalline. The subdivision, as has been 
before explained, is a fundamental feature of the « Taconic sys- 
tem.” The former of the two limestones is distinguished by 
HKmmons as the Stockbridge limestone—a name adopted by 
Prof. Edward Hitchcock for the Berkshire limestone, while for 
the Hastern Vermont belt he used the term Holian limestone. 
a. The eastern or Stockbridge limestone belt is continuous 
from near Towner’s (on the Harlem R. R., 45 miles from New 
York city), and also by a more eastern branch, from New Fair- 
field, Connecticut, nearly in the latitude of Towner’ s, to Clarks- 
burg, on the northern border of Berkshire, a distance of about 
95 miles. In North Adams, the town next south of Clarks- 
burg, the belt approaches on its west side the Williamstown 
limestone within less than a mile, but nowhere hasa direct con- 
nection with it at surface. From Williamstown the limestone 
enters Vermont and (as the Vermont geological map indicates), 
* Index to the Geology of the United States, 1820, in which he acknowledges 
the “ assistance, for two or three years, of that able and accurate naturalist, Prof. 
Dewey, of Williams College.” 
