Language Access Services About the Park About the Agency Access
to Records Geology of the Adirondack Park The Adirondack
Mountains are very different in shape and content from other
mountain systems. Unlike elongated ranges like the Rockies and
the Appalachians, the Adirondacks form a circular dome, 160
miles wide and 1 mile high. Although the Dome as we know it
today is a relatively recent development, having emerged about 5
million years ago, it is made of ancient rocks more than a 1,000
million years old. Hence, the Adirondacks are "new mountains
from Birth of a Glacier A quarter of a million years ago, when
the earth was a few degrees cooler, the snow which fell in the
winter did not melt entirely in the cool summers. As it
accumulated over millennia, its enormous weight compressed the
lower layers of snow into ice, eventually becoming thousands of
feet thick. The increased pressure softened the lower ice,
causing it to flow like thick molasses. A glacier Shaping the
Landscape As the ice advanced southwar