Cuvier’s “Revolution of the Globe”

Main contributions

• Widely read, influential work
• Goal of expanding/reforming geognosy by incorporating fossils; helped set an international research agenda
• Included analogies with study of human history

Main points

• Revolutions
  • Mental tour of transect from plains to mountains
  • Fossils throughout Tertiary and Secondary strata
  • Fossils change
    • Marine invertebrates vs. Terrestrial quadrapeds
    • Different terrestrial faunas through Tertiary
  • Sudden: some quadrapeds preserved in ice with skin, hair, flesh
  • Also inferred for Primary but no fossil evidence
    • Suggests upheaval (new feature)
  • Infer abrupt changes “revolutions”
    • Former land areas inundated
    • Cause widespread extinction of terrestrial animals
• Modern Processes
  • Inventory
    • Landslides, alluvia, dunes, cliffs
    • Deposits under water
    • Precipitates
    • Corals
    • Volcanoes
  • Conclude none are sufficient to cause faunal revolutions and disruption of strata: “The thread of operations is broken; nature has changed course, and none of the agents she now employs today would have been sufficient to produce her former works.”
• Geological Systems
  • Older Systems: Cosmologists
    • Varied stories that use Creation and Deluge in some form (some allegorical) to bring earth into its current state
  • Modern Systems: mid-late 18th century
    • Incorporate more chemistry and field observations
  • Problem with all: Too much speculation, not enough data
• How to make progress
  • Focus on observations and collect data
  • Expand study of strata to include fossils that can give evidence of changing environments and revolutions
• Use of fossils
  • Which are most reliable?
    • Marine invertebrates
      • Respond to environmental changes
      • Less affected by revolutions since these involve flooding of landscape
      • Not fully possible to know if ancient forms are extinct since much of ocean floor unstudied
    • Terrestrial quadrapeds
      • Fairly rapid turnover in section
      • Affected by the marine inundations associated with revolutions
      • Large quadrapeds are likely to be known, so extinction can be proven
    • Terrestrial record is more reliable for detecting revolutions
•  Nature of fossil record
  • As we move downward in the section
    • Youngest deposits contain modern species
    • Slightly older have new species of extent genera
    • Older have species of unknown genera
  •  Transmutation
    • Cuvier does not accept this for the reasons
      • No known mechanism
      • Comparisions of ancient (Egypt) and modern show no changes
      • Hard to imagine transitions because animals are all-integrated structures
  • Fossil Progression
    • Humans absent except in most superficial deposits
    • Mammals are limited to the most recent beds (Tertiary)
    • Reptiles and amphibians are older (Secondary)
• Human History and the Last Revolution
  • Written records of human history all end about 5-6,000 years in the past
  • Natural chronometers (De Luc) all suggest that the present landscape is quite young
    • Lake sediments, talus slopes, etc.
  • Human remains limited
  • Infer that human history postdates the last revolution
• Agenda for future research
  • Focus on field work, not speculation
  • Extend geognosy to include fossils along with lithology
  • Focus on work on Secondary and Tertiary strata
  • Compare different basins, particularly above the Chalk (i.e., Tertiary)
  • Study recent processes to better understand strata