The
Lewistown Narrows and Northern Lewistown Bypass are new construction
projects. But this construction to
benefit modern travelers lets us look at evidence of life that traveled as long as
400 million years ago. Sea creatures like algae, scallops, coral and tracks
of worms left in the sea bottom show up as fossils in excavated rocks.
The Narrows once was the bottom of a tropical sea.
As sediment drifted down in that ancient sea, it
formed the soft limestone for which the
Mifflin/Juniata area is well known. On top of
limestone the sediment became shale, and then a
layer of sandstone formed.
These layers captured prehistoric organic material, plants and animals, or their trails and burrows. In most cases, the fossils we see today were preserved with minerals, like quartz or pyrite.
Millions of years before highways, the land folded from the sea bottom to become ridges (sandstone) and valleys (limestone and shale), like the valley through which the Narrows passes. The tiny creatures and plants captured in the rock went along for the ride.
Today, we see trails and other traces
left behind as fossils that are now revealed by
excavation. Those fossils get a ring-side
view of some of PennDOT’s largest
construction projects, but many travelers
never realize they are driving through a valley of sea lilies and ancient scallops.
Click Fossil Images Below to View Larger Picture
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Copyright 2006 Maguire Group