J. D. Dana—Taconie Rocks and Stratigraphy. 205 
Arr. XXVII.—On Taconic Rocks and Stratigraphy, with a Geo- 
~ ie map of the Taconic region (Plate Il); by Jamus D. 
ANA, 
In my papers of 1873 and 1877,* on the Limestone, Schists 
and Quartzyte of the Taconic region, I present evidence 
from the facts illustrated by various stratigraphical sections, 2) 
from the continuity and common features of the conform ble 
series of these rocks from north to south, and (3) from fossils 
existing (as made known by others) in some of the beds, that 
these rocks are (A) of one system ; and (B) of Lower Silurian 
age; and (C) have the Taconic schists as the upper member of 
the series, 
Tn my work I made no attempt to map the region, since the 
Point in view was stratigraphical, with special reference to the 
lithological canon,” and its illustration did not seem to 
demand it. The evidence presented has been questioned on 
the ground (1) that the continuity of the system is not clearly 
‘tablished, and (2) that the relation of the quartzyte to the 
other rocks is not fully worked out. In order to remove as far 
’ may be, the uncertainties on these points, I began over three 
years since, a new study of the region, with reference to 1ts 
telations of the rocks, and on their distribution and geograp . 
of the pre- 
red map as well as by di 
é y diagrams. ; 
pine region is that of the Taconic rocks as first laid down by 
4 ofessor Ebenezer Emmons—these rocks including according 
ie original enunciation of his system: (1) /2¢ apc 
eg of the Taconic range and of the subordinate ridges 
tj thin the adjoining limestone area; ( I 4 
@) then the east and west sides of the Taconic Kange; an 
) whe quartzyte adjoining or within the limestone area. 
in Mo_nvestigations have extended over Berkshire county 
Massachusetts, Salisbury and Canaan in Connecticut, an 
“i adjoining eastern border of the State of New | ork. 18 
Not the whole of the true Taconic region, as it continues 
jo thward to central Vermont; but it comprises the neo 
nae Was. the special subject of Professor Kmmonss earlier 
"Vestigations, 
* This Journal, III, v, vi, 1873, and xiii, xiv, 
AM. Joup, Sot.—Tairp SERIES, Vou. XXIX, No. 171.—M 
14 
1877. 
ARCH, 1885, 
