270 =f. D. Dana—Taconie Rocks and Stratigraphy. 
clinal, but sufficient for curious variations, as may be seen by 
consulting the writer’s map of Fulton County. 
The facts that have been given lead the writer to the conclu- 
sion that the faults are of later date than the system of folds 
and that they may have been produced at a time possibly as 
late as the era of Mesozoic disturbance marked by dikes 
throughout the Triassic area of the Atlantic border. 
Art. XXX.—On Taconic Rocks and Stratigraphy, with a Geo- 
logical Map of the Taconic Regions ; by JAMES D. DANA. 
[Continued from vol. xxix, p. 443, March, 1885.] 9 
Part IL.—Tue Mippie anp Norruern Part. 
THIS part of my memoir, with the map illustrating it, covers 
the region from the southern boundary of Great Barrington to 
the northern limit of Berkshire, together with the towns of 
Pownal and Bennington in southern Vermont, and the eastern 
border of New York for a breadth of about three miles. The 
map, as with the former part, has only the limestone areas 
colored. Over the rest the kinds of rocks are indicated by 
letters. The scale of the map is half an inch to the mile.* 
The following are the subdivisions adopted beyond in the dis- 
cussion of the subject. 
I. General facts relating to the geographical distribution of the 
limestone and other rocks. 
II. The limestone and the overlying Taconic strata. 
III. The underlying quartzyte formation. 
IV. General conclusions. 
1. General facts relating to the geographical distribution of the lime- 
stone and other rocks. 
1. Wilkamstown the birthplace of the Taconic system.—The 
map accompanying this paper contains, in its northwestern part, 
the town of Williamstown; and there in connection with Wil- 
liams College were Prof. Amos Eaton in 1817 (for a single sea- 
son), Prof. Chester Dewey from 1817 to 1827, and Prof. Hbenezer 
Emmons in 1833 and for many yearsafterward. There Dewey 
investigated and was the first to investigate the Taconic rocks, 
the first to give the term ‘‘ Taconic,” as applied to the ridges, 
its present form (in 1819); the first to publish a geological 
map of the region.t As the history at this point has been writ-. 
* The map will be inserted in the following number. 
+ For his papers see this Journal, vols. i (1819), ii, (1820), viii (1824); the last 
contains his geological map of western Berkshire. 
