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.