48 - NEW YORK STATE MUSEUM 
reader a good conception of the character of the folding. It is 
quite the rule throughout this region of Taconic disturbance to find 
the strata either on edge or making high angles with the plane of 
the horizon. Many times the folds were actually overturned, and 
at times notable thrust faults or fractures' were developed, that is, 
the strata sometimes broke across and one great mass was pushed 
over another, as is well shown in many places in southeastern New 
York. These facts all go to indicate that the mountain-making 
compressive force applied to the region was of the extreme type, 
and though we have no way of telling just how high the rangé may 
have been, nevertheless the structural features and the vast amount 
of erosion since the folds were produced clearly indicate that the 
uplift was at least several thousand feet. The Green mountains, 
White mountains, Berkshire hills, Highlands-of-the-Hudson, and 
the Piedmont plateau are in a sense remnants of the great Taconic 
range. 
In passing westward from the main axis of the Taconic range, 
the folding becomes less and less intense and finally dies out alto- 
gether. This fact is well illustrated by figures 6, 8 and 9. Along 
the Hudson river near Albany, the strata are fairly well folded, 
while a few miles westward the folds disappear. Passing eastward 
from Albany into Rensselaer county, one enters a region of exces- 
sive folding. In passing westward from Poughkeepsie, the in- 
tensity of the folding diminishes somewhat, but the shale forma- 
tion is distinctly folded where it passes under the main mass of the 
Catskill mountains. Figure 6 clearly illustrates this fact. 
How do we know that the Taconic disturbance occurred toward 
the close of the Ordovicic period? Another inspection of figure 6 
will show that the strata of the next succeeding period (Siluric) 
rest directly upon the eroded edges of the folds of late Ordovicic 
rocks (see plate 25). Hence it is obvious that the disturbance oc- 
curred before the Siluric strata were deposited. What was the 
condition of the rest of the State just after the Taconic disturbance ? 
In central New York, near Utica, a distinct eroded surface at the 
summit of the Ordovician shales proves that region to have been 
dry land toward the end of the period. On the north side of the 
Adirondacks and in the Champlain valley no formation younger 
than Ordovicic shale occurs, and all evidence points to uplift of 
that area into dry land toward the close of the period. Data are 
not obtainable for western New York. To summarize: Practically 
all of northern-central, eastern, and southeastern New York (in- 
1See figures 23 and 24 for explanation of faults. 
