Geology emerged as a distinct discipline between 1790 and 1815 as an integration of various approaches to studying the earth. The traditional Anglo-American practice is to present this as a battle between the ideas of Werner and Hutton; fortunately recent analysis of the critical interval have advanced to a more nuanced view.

The underlying changes were two-fold: (1) the integration of geognosy with the study of specimens – specifically fossils; and (2) the infusion of a sense of history in the study of the earth. Up to this point, earth history had been treated through the various “theories of the earth” that either postulated a directional history dependent upon global changes, or presented an essentially eternal cycle of change. Neither left room for historical causality or chance – what is meant by “contingency”.

As geology began to emerge (and this is exactly the time when the term “geology” gained credibility as meaning more than geo-theories), there was an effort to identify a new direction for the field. Much of this was built on geognosy but was able to accommodate other ideas such as unconformities, erosional modification of landscapes, and (however it happened) the uplift of mountain ranges. (Ironically, as we will see in the next couple weeks, even as this “enriched geognosy” directed geological practice, the associated causal model was set aside.)

Harris, section 11

As you read this, you will note how the observations about volcanic regions, such as the Auvergne, helped bridge to integrating volcanism, denudation, and geological time. Much of this was overlain by a transference of ideas from human history (as argued by Rudwick) including the use of terms such as “epochs”, etc.

Rudwick (1996)

In this interesting article, Rudwick examines the mixture of practices and perspectives that merged to form geology in the early nineteenth century. His perspective differs from some commentators but is based upon a careful reading of source material. The four traditions are outlined up front and align with some of our work so far. His treatment of Cuvier and Brongniart (one of today’s readings), Cuvier’s research agenda (next reading), and Smith (following class) are useful perspectives for the readings. I should also mention that Curvier would incorporate all four “traditions” in his “Revolutions of the Earth (1812) which you will read for our next class.

Cuvier (1807)

Cuvier was one of the leading scientists of his day and held an influential position at the National Museum of Natural History (Paris). (You will learn more about him next time.) He had done extensive work on the anatomy of fossil vertebrates and developed an interest in their stratigraphic setting. This work reviews a publication, but is actually a review of the status of geology – he would return to this theme in a 1810 review of the “Progress of Geological Sciences” and in the “Revolutions of the Globe” (1812). This reading is from Rudwick (1997) – a wonderful study of Cuvier’s geological ideas and writings. He presents new translations of Cuvier’s works with insightful commentaries. There are really three main parts to this:

• Overview of the status of mineralogy, geognosy and geology (theories) – p. 101-106. This includes the great comment on “geology” on p. 103 (second paragraph “In fact it is…”).
• Presentation of a research agenda – p. 106-108. This is the most important contribution of this work. It was his initial version of how to make progress on geology. It reflects a problem Cuvier faces: how to place his fossil quadrapeds into a historical succession, and his realization that geognosy provides a time framework for doing so.
• Comments on Andres work – p. 108-111. He finally gets around to this! What does Cuvier consider as useful?  What is not?

Cuvier and Brongniart (1808) in Rudwick (1997)

This landmark paper is often cited but rarely read. Cuvier and Brongniart worked on the strata around Paris from which many of Cuvier’s vertebrate fossils originated. As you know by now, this study builds on the geognosy tradition. Rudwick’s commentary sets up this work.  Note that this is the preliminary version of the report that was published in 1811 (with an updated version in 1822).

As you read this, you should know a few things about the regional geology. The geology of northern France is marked by a set of Paleozoic “massifs” that ring a saucer-like depression that is infilled by Mesozoic and Tertiary sediments. These are exposed in a nested set of outcrop belts centered on Paris (see a geological map of northern France). Marine transgressions came from the north and northwest (i.e., the English Channel). Cuvier and Brongniart studied strata from the Late Cretaceous (Chalk = top of the Secondary rocks in 19th century terms) through Tertiary. The “Detrital Silt” is Quaternary, probably Pleistocene.

As you look through this paper, you will see that its structure is similar to many regional geology reports ever since:

• Introduction (p. 134-135)
• Geological setting: overview of topography and basin configuration (p. 134-136). Skim this since it is hard to visualize without a map of north-central France. See the map (link above) to get a sense of this.
• Stratigraphic summary (with column and geological map) (very bottom of p. 136-138, also see section on p. 147): Overview of the units
• Details of lithology, fossils, distribution (p. 139-156): All the details! Skim to get a sense of what is included. You need only extract some of the basic information – see questions below.
• Conclusion (p. 156): Brief  note on coming attractions – see the footnote.

To do

• What is your understanding of the four practices identified by Rudwick?
  • What kind of activities (laboratory, fieldwork, etc.) and results (publications, mines, etc.) would follow from each of these traditions?
  • Do these practices make sense in light of what you know about geology circa 1800?
  • What does Rudwick mean by geology becoming a “historical” science?
• Cuvier 1807
  • What is his opinion of the various earth sciences (Rudnick’s traditions)?
  • What is his proposal for future research?  Why would it be useful?
  • Compare his prosposed agenda to what a “geognosy” agenda might have been – what is similar and what is different?
• Cuvier and Brongniart (1808)
  • Compile a list of formations and units within them
  • What are the lithologies and fossils within each unit?
  • What is the environment of deposition?
• Finally, what kind of activities would an aspiring geologist of (say) 1810 have attempted? What would have been the goals of such work?

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