Geology circa 1800-1810

Rudwick (1996): Four practice that converged to make geology

• Study of Specimens
  • Study of specimens of minerals, rocks or fossils
  • Lab study; removed from their field occurrence
  • Museums and private collections
  • Cuvier and Brongniart would bring this back to the field
• Geognosy
  • Three-dimensional structural science
  • Specific sequence and positions of gebriges
  • Organized lot of geological information
  • Framework for future work
  • Common throughout late 19th century
• Histories of the Earth
  • Broad and generalized models of earth history
  • Process-based interpretation
  • Not closely tied to field observations
  • About 87 tabulated: cosmologists through Hutton
  • Held in low regard by late 18th century
• Concept Transfer from Human History
  • Use the language of studies of human history: “monuments”, “archives”
  • Suggest using fossils as evidence of past temporal sequence (Smith, Cuvier)
  • Suggest a chronology possible
  • Also suggest contingent events – exploited by Cuvier

Cuvier (1807): State of studies of the earth

• Knowledge about the earth fell into two major categories
  • Geognosy
    • Descriptive work on minerals, rock types, fossils, geognosy
    • Reliable and objective
  • Histories of the Earth
    • Speculative and not well-rooted in fact
    • Aka: geology
• Agenda for moving forward
  • Study of mountain ranges and adjacent areas
    • Succession of gebriges
    • Relationship of gebriges, dip and topography
    • Extension of beds
  • Fossil studies
    • Fossils associated with gebridges
    • Is extinction real?
    • Relation of past organisms and climate
    • Are fossils in place or transported
  • Shape of valleys and origin (i.e., landscapes)

Cuvier and Brongniart (1808): Paris Basin: Stratigraphic Summary

Unit	Rock Type	Fossils	Environment
Detrital Silt	Sandstone, pebbles	Quadrapeds	Terrestrial
Freshwater Formation	Siliciclastic-rich limestone	Non-marine shells	Freshwater
Sandstone without Shells	Sandstone	None	? Non-marine
Marine Sandstone	Sandstone	Marine shells	Marine
Gypsum Formation	Gypsum, marls	Freshwater mollusks, quadrapeds	Freshwater
Coarser Limestone – Siliceous Limestone	Limestone with some sand	Marine shells (>600 species)	Marine
Plastic Clay	Clay/soft shale	None	Freshwater
Chalk	Limestone	Marine shells	Marine

Notes

• The Chalk is the top of the Secondary strata and the top of Werner’s detailed work. Rest is what would be termed Tertiary.
• Cuvier placed his terrestrial vertebrate faunas in the various non-marine units, indicating changes through time.  Lower units had faunas more dissimilar to modern.