Early Geology
Interpretation of Fossils
• Was the origin of fossils biotic, spontaneously generated, signs placed in rock by God...?
• Nichlas Steno (1669) studied fossils in Italy; concluded that they were biotic, formed in ancient sea beds.
• Eventual consensus among scientists with Steno.
• Unique fossil forms discovered; increasing unlikelihood that these forms were still extant.
• Theological issues raised regarding extinction; pre-human history
Interpretation of Fossils
• Was the origin of fossils biotic, spontaneously generated, signs placed in rock by God...?
• Nicholas Steno (1669) studied fossils in Italy; concluded that they were biotic, formed in ancient sea beds.
• Eventual consensus among scientists with Steno.
• Unique fossil forms discovered; increasing unlikelihood that these forms were still extant.
• Theological issues raised regarding extinction; pre-human history
Early Theories of the Earth
• Descartes (1644) gives a “Hypothetical” developmental origin of the earth
• de Fontanelle (1688): The Plurality of Worlds
• Thomas Burnet (1691): Sacred Theory of the Earth - dead star; collapsing crust, waters flood from below; return to a star
• William Whiston (1696): New Theory of the Earth - gravitational attraction; comet- deposited waters of a flood
• Leibniz & Hooke (end of 17th cent.) propose a cooling earth - “vulcanism”
Early Theories of the Earth
• Descartes (1644) gives a “Hypothetical” developmental origin of the earth
• de Fontanelle (1688): The Plurality of Worlds
• Thomas Burnet (1691): Sacred Theory of the Earth - dead star; collapsing crust, waters flood from below; return to a star
• William Whiston (1696): New Theory of the Earth - gravitational attraction; comet- deposited waters of a flood
• Leibniz & Hooke (end of 17th cent.) propose a cooling earth - “vulcanism”
Early Theories of the Earth (18th Century)
• de Maillet’s Telliamed (1748) provides a neptunist, ancient explanation
• Buffon’s Histoire Naturelle (1749) suggests cometary impact and 6 ages of geology
• Kant (1755) proposes a nebular hypothesis of the solar system
• William Herschel’s astronomical observations add strength to later nebular explanations such as those of Laplace (1803).
Early Theories of the Earth (18th Century)
• de Maillet’s Telliamed (1748) provides a neptunist, ancient explanation
• Buffon’s Histoire Naturelle (1749) suggests cometary impact and 6 ages of geology
• Kant (1755) proposes a nebular hypothesis of the solar system
• William Herschel’s astronomical observations add strength to later nebular explanations such as those of Laplace (1803).
1700s: Neptunists & Vulcanists • Neptunists: geologic strata result from
retreating seas; rocks are sedimentary
• Vulcanists: a hot earth cools with volcanic rock and earthquakes raising continents.
• A.G. Werner: a neptunist; helped formulate the law of superposition.
• Not all neptunists were biblicists, but most biblicists were neptunists.
• Scriptural geologists advocated a literal reading of Genesis.
• James Hutton: a vulcanist; earth’s history cyclical: “… no vestige of a beginning, no prospect of an end.”
Stratigraphic Column
• Sedimentary rock is often multi-layered, deep, and tilted.
• Law of superposition gives relative age of rocks, but not absolute.
• Strata of different locations could be correlated by fossils.
• Economic incentive for understanding geology.
• Late 1700s - 1800s developed a sequential “stratigraphic column” of all rocks throughout the world
• Column was divided into eras, periods and epochs.
• Majority accepted an ancient earth due to the depth of the column, unconformities, complex ineractions of rocks, variety of fossils, etc.
Stratigraphic Column
• Sedimentary rock is often multi-layered, deep, and tilted.
• Law of superposition gives relative age of rocks, but not absolute.
• Strata of different locations could be correlated by fossils.
• Economic incentive for understanding geology.
• Late 1700s - 1800s developed a sequential “stratigraphic column” of all rocks throughout the world
• Column was divided into eras, periods and epochs.
• Majority accepted an ancient earth due to the depth of the column, unconformities, complex interactions of rocks, variety of fossils, etc.
Philosophical & Theological Issues
• The concept of an ancient earth again challenged human self- perception
• Catastrophists: earth history is a result of processes and events of sudden and violent nature that cannot be observed today.
• Uniformitarians (e.g. Lyell): reliance on processes that cannot be observed today is unscientific. Slow, gradual processes of today can explain all earth’s features.
• Some scientists used theories regarding the earth to advocate a form of scientific naturalism.
• Mosaic (scriptural) geologists were a minority in British science.
• Distrust of divisive theories in geology was abandoned by many scientists in favor of empirical description and utility. It excluded as unscientific discussion of age and formation of the earth.
