270 J. D. Dana—Southward ending of a 
The subdivision of the Taconic system into an older and a 
newer Taconic was first made by Professor Emmons, the pro- 
bred of the system. But the division was not based on any 
acts connected with the original Taconic rocks—those of the 
Taconic Range—but on the perplexing facts that beset the 
subject after additions of other Taconic rocks and regions had 
been made. No facts favoring in the least such a subdivision 
have been reported from the Taconic Range. 
Among those broader portions of the Taconic Range in which 
the pitch of the beds is for the most part toward the axis of 
the mountain and in this fact bear positive evidence of a syn- 
clinal structure, there is the elevated region called Mount 
ashington, situated in southwestern Massachusetts and north- 
western Connecticut. This Mt. Washington portion of the range 
is that referred to in the title of my paper—“On the Southward 
ending of a great Synclinal in the Taconic Range ;’ and to the 
description of it I now proceed. 
Mount Washington rises boldly above the limestone plains 
and valleys adjoining it. Its length is about twelve miles, and 
its average width five miles. The limestone area on the east of 
it, in Sheffield, Massachusetts, and the bordering part of Con- 
necticut, is nearly ten miles wide, and that on the west, in 
Copake, about three miles wide. The summit of Mount Wash- 
ington (called Mt. Everett) has a height of 2,624 feet above the 
sea. ‘I'he mean height of the extensive summit region is over 
2,000 feet, and 1,300 feet. above the limestone plains at its 
eastern, western and southern base. ‘ 
The accompanying map shows, on a scale of 0°8 inch to the 
_ * The map accompanying this article, presented to the British Association, 
included the whole of Mount Washington. I propose to publish soon a MP 
of all of Berkshire, and another of Salisbury and Canaan, with full details. 
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