4 
210 3S. D. Dana—Taconic Rocks and Stratigraphy. 
paper of 1877, following that on Wing’s discoveries, I left the 
question of age undecided, under the idea, urged by Wing and 
others, that the stratification might have. been reversed by 
overthrust folds. Again, in my paper of 1879, the doubt is 
admitted ; and in that of February, 1882, presented to the 
Geological Society, in which the subject is briefly reviewed, I 
go still further toward the opinion that the quartzyte 1s 
“mainly if not wholly, Primordial.” In this state of mind, I 
commenced in the summer of 1882 the new investigations, 
determined to remove, if possible, the doubt on the question 
as to reversals by overturn flexures; and the final conclv- 
sion is essentially identical with that of 1873. : 
The conclusions arrived at make the headings of the subdi- 
visions in this and the following part of my paper, and are as 
I. The limestone formation is overlaid conformably by the 
schists of the Taconic range and of other ridges of the region 
east and west of the range. 
II. The limestone east of the Taconic range is overlaid con- 
formably by strata of quartzyte and quartzytic and ordinary 
mica schis : a 
III. The limestone is a single continuous formation; the 
same is true of the overlying schists and quartzyte. 5 
I e limestone is underlaid, near or along part of its 
eastern border, by strata of quartzyte and associated mica schist. 
V. Within the Taconic region, crystalline texture and min- 
eral constitution are geographically gradational ; that is, vary 
gradually from north to south and similarly from west to eas 
The topics are to a considerable extent the same as In MY 
former papers. But they are illustrated by new facts, with 
the aid of the new map and many new stratigraphical sections, 
and lead to some new results. 
Part I—Tue Soutrnuern Portion or THE REGION. 
IL The Limestone formation underlies the Schists of the Taconic 
nge and of other associated ridges. 
On the map, accompanying this paper, the reader has pit 
him the facts as to the distribution of the limestone (the colore 
