Geology Reference
In-Depth Information
Through his observations of sites such as Siccar Point — a rocky area along
the east coast of Scotland — Hutton began describing geologic processes that re-
quired long periods of time to create the rock formations visible today. He was the
first geologist to propose the idea of geologic time, also called
deep time,
which
extended the age of the earth much farther into the past than had previously been
accepted.
According to Hutton, with a long enough period of time, even the small, commonplace
processes that shape the earth's surface today could result in the dramatic formations
previously assumed to be the results of catastrophe.
Finding sharks' teeth on mountaintops
Nicholas Steno scientifically examined the head of a shark and reported that the teeth in the shark's
head were very similar to stones found in the mountains. These stones were called
glossopetrae,
or
“tongue stones,” and at the time were believed to result from lightning strikes. Indeed, what Steno had
discovered was that sharks' teeth were actually buried in the rocks on the mountaintop!
What has been will be: Lyell's principles
Following Hutton's work, Charles Lyell, a Scottish professor of geology in the early nine-
teenth century, published a topic called
Principles of Geology.
In this topic Lyell outlined
and expanded on Hutton's ideas about deep time, geologic processes, and the formation
of rock features on earth's surface.
In publishing his topic, Lyell spread Hutton's ideas and popularized them. The concept
that “the present is the key to the past” was groundbreaking at the time and inspired sci-
entific thought in fields outside of geology, such as Darwin's ideas about evolution.
The basic principle that Hutton proposed, called
uniformitarianism,
is still the
foundation of geologic science. Simply put, it states that past geologic phenomena
can be explained by drawing on observable processes occurring today.
