1796, William Smith (1769-1839), an English geologist,
found he could identify individual layers of rock
by the fossils
unique to each layer (Winchester, 2002, pp 116-117). Smith
was able to map out the succession of fossils found in
different rock formations. His geologic maps showed that
life forms appear and disappear through time.
Cuvier (1769-1832), the great French anatomist set the
for the new
paleontology. In his historic lecture of 1796, Cuvier
established extinction as a fact using evidence from fossil mammoths.
Cuvier was also the first to note mass extinctions
at what we now define as the end of the Paleozoic and
George Cuvier and Alexandre Brongniart (1770-1847), a
French naturalist and geologist mapped the Paris Basin.
In reconstructing the changing sea levels of the Atlantic Ocean
Brongnairt and Cuvier showed that fossils had been laid down during
alternating fresh and salt-water conditions thus establishing the
fact that there existed a succession of fossils in different formations
representing different environments.
A History of Life on Earth
noticed that the more ancient a fossil the less it resembled
present day organisms. In ordering fossils chronologically
Cuvier, like Smith, was constructing a history of life
on Earth using geologic strata. Thus began the science
biostratigraphy. Cuvier was opposed to early theories of evolution
and viewed faunal succession as evidence
for a cycle of creation and extinction
of Catastrophism. Cuvier's vital contributions to our understanding
of geologic time are
As Michael Benton (2001), an English paleontologist, points
out Cuvier was unable to "...make two vital connections:
and evolution, and between geological change and time (p. 99)."
Stephen J. Gould (1941-2002), an American evolutionary biologist,
believed the geologic time table to be one of the greatest
contributions to human understanding (2001).
establishment of a time scale, and the working out of a
consistent and worldwide sequence of changes in fossils
through the stratigraphic record, represents the major
triumph of the developing science of geology during the
first half of the nineteenth centruy....By 1850, geology
had developed a coherent global chronology based on life's
history. This discovery and construction of history itself
must rank as the greatest contribution ever made--indeed,
I would argue, ever makable--by geology to human understanding.
Changing Patterns of Life
continue to discover evolutionary patterns of life on
Earth by correlating
fossil discoveries to the geologic time table. Students
changing life patterns though time as they explore
the fossil record in our
dropdown menus above can be used to visit each time period.
In each time period you will find an introduction along
galleries. Introductions identify major life forms that
existed during the geologic period. Fossil galleries provide
visual examples of organisms from specific fossil deposits. Use
our museum for time travel. Trace your journey keeping
track of the appearance and persistence of life forms through
related to geologic time and permineralized plant material
can be found on the sidebar menu. The information and exercises
provided in the sidebar menu can deepen your understanding
of geologic time, how fossils form, and the history of life
on Earth, a revelation from the fossil record.