History of Geology:
Early Misconceptions

• Origin of fossils
• Aristotle (Greece, 4th century B.C.)—with regard to fossil fish: "a great many fishes live in the Earth motionless and are found when excavations are made"
• Mercati (Italy, 1574)—"fossils shells are mere stones which had assumed their peculiar configuration from the influence of heavenly bodies"
• Age of Earth
• Dilemma: reconciling geologic features with religious teachings
• Archbishop Ussher (mid 1600’s: Earth created 4004 BC and is about 6000 yr old)
• _____________________________—geologic features formed by relatively short-lived catastrophic events

Modern Geology

• ________________________—"father of modern geology"
• 18th Century Scottish physician
• Carefully observed geologic features and natural processes
• Developed a principle called Uniformitarianism

Expansion of Hutton’s "Theories"

• John Playfair: "Illustrations of the Huttonian Theory" (1802)
• _______________________l: "Principles of Geology" (1830-1872) (Subtitle: "Being an Attempt to Explain the Former Changes of the Earth’s Surface, by Reference to Causes now in Operation")

Modern Geology (cont.)

• ____________________________
• The physical, chemical, and biological laws that operate today operated in the geologic past
• Processes active today are responsible for geologic features
• To paraphrase: "the present ____________________________"

Catastrophism versus Uniformitarianism

• Mountain-building
• Deposition of thick sediment accumulations
• Erosion of Badlands
• Erosion of Channeled Scablands
• Snowball Earth?
• Asteroid impact