58 NEW YORK STATE MUSEUM 
APPALACHIAN MOUNTAIN REVOLUTION (CLOSE OF THE 
PALEOZOIC) 
The Paleozoic era was brought to a close by one of the most pro- 
found physical disturbances in the history of North America. It has” 
been called the Appalachian revolution because at this time the Ap-— 
palachian mountain range was born out of the sea by upheaval and 
folding of the strata. Because of the direct effect of this great 
upheaval upon the history of New York State, a brief description 
is given. mas | 
All through the vast time (probably ten million years) of the 
Paleozoic era, a great land mass existed along what is now the” 
eastern coast of North America. This land, which has been called 
Appalachia, had its western boundary approximately along the 
present coast line, while it must have extended eastward at least 
as far as the present border of the continental shelf. Concerning the 
altitude and character of the topography of Appalachia we know 
almost nothing, but we do know that it consisted of metamorphic 
rock of Precambric age, and very similar to that of the Adirondacks. 
The tremendous amount of derived sediments shows that Appala- 
chia was high enough during nearly all its history to undergo 
vigorous erosion. Although oscillations of level more than likely 
affected Appalachia, and its western shore line was quite certainly 
somewhat shifted at various times, nevertheless it persisted as a 
great land-mass with approximately the same position during all 
its long history. Its general position is well shown on the map, 
figure 16. 
Barring certain minor oscillations of level, all the region just 
west of Appalachia was occupied by sea water during the whole 
Paleozoic era, and sediments derived from the erosion of Appala- 
chia were laid down layer upon layer upon that sea bottom. The 
coarsest and greatest thickness of sediments was deposited nearest 
the land, that is along what we might call the marginal sea bottom. 
At the same time finer sediments, in thinner sheets, were being 
deposited all over the Mississippi valley region. By actual measure- 
ment, in the present Appalachians, we know that the maximum 
thickness of these sediments was at least 25,000 feet. These are 
all of comparatively shallow water origin, as proved by the coarse- 
ness of sediment, ripple marks, fossil coral reefs ete., and so we 
are forced to conclude that this marginal sea bottom gradually sank 
during the process of sedimentation, thus producing what is called 
a great geosynclinal trough. Perhaps the very weight of accumu-~ 
