Giants of Geology

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Giants of Geology
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Nicola Steno 1638 - 1686
1669-Niels Stensen (Steno) publishes Forerunner,
showing diagrammatic sections of the Tuscany area
geology, making the important point that
sediments are deposited in horizontal layers.
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Stenos Laws
Steno's law of superposition layers of rock are
arranged in a time sequence, with the oldest on
the bottom and the youngest on the top, unless
later processes disturb this arrangement. It is
Steno's most famous contribution to geology.
Steno essentially abandoned science after his
conversion to Roman Catholicism in 1667, much to
the dismay of some of his scientific colleagues.
He was ordained as a priest in 1675. In 1677, he
became a titular bishop, and spent the rest of
his life ministering to the minority Roman
Catholic populations in northern Germany,
Denmark, and Norway.
Steno's principle of original horizontality
states that rock layers form in the horizontal
position, and any deviations from this position
are due to the rocks being disturbed later.
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Nicola Steno Fossils
While examining the teeth of the shark, Steno was
struck by their resemblance to certain stony
objects, called glossopetrae or "tongue stones,"
that were found in certain rocks. Ancient
authorities, such as the Roman author Pliny the
Elder, had suggested that these stones fell from
the sky or from the moon. Others were of the
opinion, also going back to ancient times, that
fossils naturally grew in the rocks. Steno's
contemporary Athanasius Kircher, for example,
attributed fossils to a "lapidifying virtue
diffused through the whole body of the geocosm."
Steno, however, argued that glossopetrae looked
like shark teeth because they were shark teeth,
that had come from the mouths of once-living
sharks, and come to be buried in mud or sand that
was now dry land.
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Robert Hooke (1635-1703)
No portrait survives of Robert Hooke. His name is
somewhat obscure today, due in part to the enmity
of his famous, influential, and extremely
vindictive colleague, Sir Isaac Newton. Yet Hooke
was perhaps the single greatest experimental
scientist of the seventeenth century. His
interests knew no bounds, ranging from physics
and astronomy, to chemistry, biology, and
geology, to architecture and naval technology he
collaborated or corresponded with scientists as
diverse as Christian Huygens, Antony van
Leeuwenhoek, Christopher Wren, Robert Boyle, and
Isaac Newton. Among other accomplishments, he
invented the universal joint, the iris diaphragm,
and an early prototype of the respirator
invented the anchor escapement and the balance
spring, which made more accurate clocks possible
served as Chief Surveyor and helped rebuild
London after the Great Fire of 1666 worked out
the correct theory of combustion devised an
equation describing elasticity that is still used
today ("Hooke's Law") assisted Robert Boyle in
studying the physics of gases invented or
improved meteorological instruments such as the
barometer, anemometer, and hygrometer and so on.
He was the type of scientist that was then called
a virtuoso -- able to contribute findings of
major importance in any field of science. It is
not surprising that he made important
contributions to biology and to paleontology.
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Robert Hooke (1635-1703)
Hooke examined fossils with a microscope -- the
first person to do so -- and noted close
similarities between the structures of petrified
wood and fossil shells on the one hand, and
living wood and living mollusc shells on the
other. In Micrographia he compared a piece of
petrified wood with a piece of rotten oak wood,
and concluded that this petrify'd Wood having
lain in some place where it was well soak'd with
petrifying water (that is, such water as is well
impregnated with stony and earthy particles) did
by degrees separate abundance of stony particles
from the permeating water, which stony particles,
being by means of the fluid vehicle convey'd, not
onely into the Microscopical pores. . . but also
into the pores or Interstitia. . . of that part
of the Wood, which through the Microscope,
appears most solid. . .
Hooke had grasped the cardinal principle of
paleontology -- that fossils are not "sports of
Nature," but remains of once-living organisms
that can be used to help us understand the
history of life. Hooke realized, two and a half
centuries before Darwin, that the fossil record
documents changes among the organisms on the
planet, and that species have both appeared and
gone extinct throughout the history of life on
Earth.
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Robert Hooke (1635-1703)
Perhaps his most famous microscopic observation
was his study of thin slices of cork, depicted
above right. In "Observation XVIII" of the
Micrographia, he wrote . . . I could
exceedingly plainly perceive it to be all
perforated and porous, much like a Honey-comb,
but that the pores of it were not regular. . . .
these pores, or cells, . . . were indeed the
first microscopical pores I ever saw, and
perhaps, that were ever seen, for I had not met
with any Writer or Person, that had made any
mention of them before this. . . Hooke had
discovered plant cells -- more precisely, what
Hooke saw were the cell walls in cork tissue. In
fact, it was Hooke who coined the term "cells"
the boxlike cells of cork reminded him of the
cells of a monastery.
1668-Robert Hooke presents a lecture to the Royal
Society claiming that earthquakes, not the
biblical flood, have caused fossils to be found
on mountaintops and buried in stone.
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William Smith (1769-1839)
Fossils have been long studied as great
curiosities, collected with great pains,
treasured with great care and at a great expense,
and shown and admired with as much pleasure as a
child's hobby-horse is shown and admired by
himself and his playfellows, because it is
pretty and this has been done by thousands who
have never paid the least regard to that
wonderful order and regularity with which nature
has disposed of these singular productions, and
assigned to each class its peculiar stratum.
William Smith, notes written January 5, 1796
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William Smith (1769-1839)
Smith observed that the fossils found in a
section of sedimentary rock were always in a
certain order from the bottom to the top of the
section. This order of appearance could also be
seen in other rock sections, even those on the
other side of England. As Smith described it, .
. . each stratum contained organized fossils
peculiar to itself, and might, in cases otherwise
doubtful, be recognized and discriminated from
others like it, but in a different part of the
series, by examination of them. This is a
statement of the "principle of faunal
succession."
1815-Relying largely on fossils to identify
strata, civil engineer William Smith publishes a
geologic map of England, Wales and part of
Scotland, the largest region so far documented.
Four years later, Smith will be arrested and sent
to debtors' prison.
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William Smith (1769-1839)
In 1796, Smith was elected to the agricultural
society at Bath, and began to discuss his ideas
with others who were interested in rocks and
fossils. He began to write notes and draw up
local geologic maps. Smith was not the first to
make geologic maps, but he was the first to use
fossils as a tool for mapping rocks by their
stratigraphic order, and not necessarily by their
composition. Previous mapmakers had attempted to
use the composition of rocks as indicators of
their position in the stratigraphic column.
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William Smith (1769-1839)
In 1799, Smith's employment with the
canal-building firm came to an end. Smith then
took a series of engineering jobs in several
parts of Britain, and made a number of side trips
all over England and Wales. His goal was to
produce a complete geologic map of England and
Wales, using the principles of fossil succession.
Progress was slow, and money to finance the
publication of such a map was hard to find.
Finally, with the aid of 400 subscribers
underwriting the project, production of the
completed map began in 1812, and in 1815 the map
was finally published.
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James Hutton 1726 - 1797

• In the late 18th century, the educated world
  clung to the Neptunian theory of the earth
  proposed by Abraham Gottlob Werner. Known as the
  father of geology, James Hutton overturned the
  Neptunian orthodoxy and instead proposed his own
  Plutonian theory. In the rocks of Scotland,
  Hutton found fingers of granite reaching well
  into sedimentary rocks, and saw this as evidence
  of subterranean fire and heat. He also found
  neatly deposited layers of sedimentary rocks
  overlaying rock layers that were almost vertical,
  as shown at right. The lower layers of rock, he
  concluded, must have been deposited eons before,
  then later upturned. In them, Hutton saw evidence
  of vast expanses of time in earth's history.
  (Charles Lyell was following in Hutton's
  footsteps when he wrote his own masterwork in
  1830.)

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James Hutton 1726 - 1797

• 1794-James Hutton publishes An Investigation of
  the Principles of Knowledge. Buried in the
  2,138-page philosophical tome is a chapter about
  variety in nature in which Hutton anticipates
  Charles Darwin's theory of natural selection.
• 1795-James Hutton overturns the "Neptunian" view
  of rock formation in his Theory of the Earth,
  suggesting instead that forces of rock creation
  are balanced by forces of rock destruction.

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Charles Lyell 1797 - 1875

• In August 1838 Lyell published the Elements of
  Geology, which, from being originally an
  expansion of one section of the Principles,
  became a standard work on stratigraphical and
  palaeontological geology. This book went through
  six editions in Lyell's lifetime (some
  intermediate editions being styled Manual of
  Elementary Geology), and in 1871 a smaller work,
  the Student's Elements of Geology, was based upon
  it. His third great work, The Antiquity of Man,
  appeared in 1863, and ran through three editions
  in one year. In this he gave a general survey of
  the arguments for man's early appearance on the
  earth, derived from the discoveries of flint
  implements in post-Pliocene strata in the Somme
  valley and elsewhere he discussed also the
  deposits of the Glacial epoch, and in the same
  volume he first gave in his adhesion to Darwin's
  theory of the origin of species. A fourth edition
  appeared in 1873.

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Charles Lyell 1797 - 1875

• Catastrophism, was attacked in 1830 by a
  British lawyer-turned-geologist named Charles
  Lyell (1797-1875). Lyell started his career
  studying under the catastrophist William Buckland
  at Oxford. But Lyell became disenchanted with
  Buckland when Buckland tried to link
  catastrophism to the Bible, looking for evidence
  that the most recent catastrophe had actually
  been Noahs flood.

• Lyell wanted to find a way to make geology a
  true science of its own, built on observation and
  not susceptible to wild speculations or dependent
  on the supernatural.

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Timeline of Evolutionary Thought
This slide shows the history of evolutionary
thought from 1700 to the present in terms of the
life spans of the principal figures involved.
Note that some geologists are included here. This
would be a suitable topic for a class paper,
treating either the entire timeline shown to the
left or selected parts. The internet and the
library at the back of the lecture room (Dow 615)
are good resources. The url at the bottom of the
page is for the Berkeley site from which the
figure is taken. This is a good site to visit and
study, one of the best in the world and suitable
even for high school students and laymen.
http//www.ucmp.berkeley.edu/history/evotmline.htm
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