Geology Reference
In-Depth Information
at the end of the millennium (although, as we'll see, opinions differed as to just when that
would be).
Later in the Renaissance, the rediscovery and translation of influential Greek and Arabic
philosophical texts blurred the distinction between living and nonliving things. If Earth it-
self was alive, perhaps fossils, a name that covered any odd thing found in a rock, could
grow in rocks. Stalactites dripping from the ceiling of caves grew within the earth. Why
not fossils too? Such thinking led natural philosophers to see fossils as objects that simply
mimicked the shapes of living organisms. While natural philosophers came to regard fossils
as nothing more than mineral curiosities, a few, like Leonardo da Vinci, thought otherwise.
Late in the fifteenth century, the rivers and hills of northern Italy fascinated the son of a
public official in the town of Vinci, nestled at the foot of Monte Albano. As a boy Leonardo
wandered up the mountain and found a cave where the rock walls were a hash of seashells
and fish bones. A natural skeptic, he didn't believe the common explanation that Noah's
Flood had carried the shells into the mountains. His doubts were strengthened when, years
later, he worked on canal projects where excavations exposed numerous fossils embedded
in solid rock. Observing his surroundings, Leonardo concluded that a great flood did not
entomb marine life in stone. Some shells were clamped shut, as if buried alive. Others were
broken into fragments and scattered in deposits resembling modern beaches. The surfaces
of rock layers even preserved worm tracks. He may have been the first to question whether
worms could crawl around the seafloor and leave perfectly shaped, undisturbed tracks dur-
ing an epic flood.
Watching how flowing water moves sediment, Leonardo concluded that no flood could
have carried ancient seashells into the mountains for the simple reason that fossils and other
objects heavier than water sank to the bottom of a current. Fossils were neither souvenirs
of the Flood nor inanimate curiosities. Either God was trying to trick him, or the story was
more complicated than implied by a simple reading of Genesis.
Leonardo reasoned that layers of sedimentary rock initially formed from mud that gradu-
ally settled to the bottom of an ancient sea. Fossil shells preserved in the rocks high on
ridges were deposited during an era of higher sea level. Trusting reason and the testimony
of his own eyes to decipher the structure of God's grand design, he saw no evidence of a
catastrophic deluge.
