Over the next few classes we will be examining the development of geology in the first half of the nineteenth century. There was general agreement on the type of work that needed to be done, but considerable controversy about theoretical and interpretative issues. Topically, the focus was on stratigraphic geology and tectonics. This set of readings provide some general background on how this came about, even if some of them (Laudan) jump forward a bit in time.

Harris section 13

Provides the usual overview with an emphasis on how stratigraphic geology developed through the 1820s. This is basically the foundation for geological work through the mid-19^th century.

Rudwick (2005), The Order of Strata, p. 431-445

This section nicely summarizes William Smith’s work and its significance. The first section points out the scientific isolation of Britain – it would take the generation of Buckland and Conybeare to fully integrate British geology into the Continent. Subsequent sections address Smith’ work as a surveyor, mapmaker and geognost.

Laudan (1987) ch. 7

This is a rather long chapter that puts early 19th century geology in a “Wernerian” (i.e., geognosy) perspective. You should focus on the discussion (p. 138-170) of how geognosy led directly to the role of formations, stratigraphic studies and mapping activities, correlation, and the conceptual issues encountered in such work (basically stratigraphic geology). Do not worry too much about all the names – pay attention to the underlying issues and concerns. I think she overstresses the historical (stratigraphic) versus causal (tectonic) divide in geology, and may undervalue Smith’s contributions (while I agree that they have been overstated by many authors). More importantly, I think that the use of formations did not serve to separate historical and causal geology – formations are not just stacked rock units, but are defined by their lithology, and thus link environmental changes to time.

If you have the energy, feel free to read the remainder of the chapter. The next section (p. 170-178) jumps ahead to a question that arose in the later 1820s: can extinct fossils be used to reconstruct past climates? This gets a bit technical so try not to get bogged down – hopefully the general point is clear that this was not a simple matter. We will see the link to Lyell’s work in the 1830s next time. The last short section (p. 178-179) introduce Rudwick’s argument for the “directional synthesis” – we will be analyzing that paper in a future class.

Buckland (1821)

This is one of the earliest attempt to correlate British and Continental strata. Notice that this paper was originally read before the Geological Society of London. Unless you are interested in the development of Alpine stratigraphy, please just read over three short sections:

• Introduction that discusses the errors of past correlations (p. 450-451): nice statement of the problems of international correlations.
• General structure of the Alps (section I, middle p. 452 – middle p. 453): compare to the standard geognosy model of mountain structure.
• Table of correlation (bottom p. 462-465): what data are in the table?

Questions

• Visual displays
  • What was the goal of the visual displays developed in the early 19^th century?
  • Why were they needed?
  • Also: please ask if you have questions about the visual displays!
• Maps
  • What was conceptually needed to produce a geological map?
  • How did Smith’s experiences provide him the background to produce his map?
  • Was Smith (and the other mapmakers of the day) practicing geognosy?
• Formations
  • Formations are often described as a “mappable unit”. What does this really mean?
  • How did the meaning of a “formation” change from Werner to the 1820s stratigraphic geology usage?
  • What was the significance of designating formations by lithology versus by age? What did each perspective allow and obscure?
  • What was the implication of finding deformed Tertiary strata (Webster 1814) and well-lithified Tertiary strata in the Alps (Brongniart 1820s)?
• Correlation
  • What criteria were available to a geognost? How well did they work?
  • What were the conceptual issues with using fossils?
  • How was the Tertiary figured out?
  • Compare the table of correlation in Buckland (1821) to that of de la Beche (1824) (p. 160 in Laudan). What criteria were used at this point in time?
• Recall Cuvier’s (1812) agenda for geological research.
  • What elements of that agenda were actively investigated in the next 10 years?
  • What still needed to be done?
  • Looking back, what were the advantages of this agenda?
• Geology around 1822-24
  • What skills and knowledge would  be needed by a geologist of 1822?
  • What problems would they address?
  • What had changed since 1810?
• One of the themes that runs through these texts is the issue of how to reconstruct the past.
  • What could be inferred from lithology? Fossils?
  • How could we go about inferring variations through time?

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