The Great Devonian Controversy
Geologic Upheaval of the 1830s
In this case study...
We explore the historical debate over the Devonian period and what this means for how Geology tries to recreate the deep past using modern evidence
Historical case study by: Jessica Burylo
THINK [1]: What is your understanding of scientific knowledge? Where does it come from and what makes it scientific?
Section 1: Setting the Stage
Greenough: Order! Order here! Good sirs would you please settle down? That’s right, take your seats. Yes, well then, welcome. I call this meeting of the Geologic Society of London to order. Thank you for attending. Our first presenter has been mapping the strata of Devonshire these last months and is here to present his findings. It cost him greatly beyond his means to travel here, so please welcome, Mr. Henry de la Beche!
de la Beche: Thank you everyone. As George has mentioned, I have been examining the strata of Devonshire, for the purposes of mapping. Namely, I have found interest in the Cambrian layer of greywacke, labeled to this time period by our own, Roderick Murchison. It is of considerable interest to me because though he presumed this layer as being without fossils, I have discovered some flora.
Murchison: Poppycock! Any scholar of stratigraphy who truly knows their subject could have never made such preposterous conclusion!
Greenough: Sit down, Roderick, Henry has the stage at this time.
de la Beche: Er, thank you, George. As I was saying. In this layer, I have discovered some fossilized flora and immediately sent samples of such to Mr. Lonsdale. He concluded that these specimens actually match flora that have previously been known to reside much later in the past, in the Carboniferous period. According to the Law of Faunal Succession, I believe I am in sound mind to reassign the greywacke as being Carboniferous in age.
Greenough: Thank you for your assessment, Henry. Considering that your conclusion is in direct opposition to the findings of Roderick, I deem it fair to allow him the stage to defend his work.
Murchison: Thank you George. I am utterly insulted that a man of de la Beche’s standing believes he could use such a controversial theory as the Law of Faunal Succession to undermine my work.
de la Beche: Oh, come now, Roderick. It is a commendable idea that fossil content might be used to associate undated strata with other layers at a known time.
Murchison: Until the time as come that this society has unanimously decided that it is, in fact, commendable, it may not be used to make such wild claims. Organisms may not all become extinct at the same time, rendering some geographic localities to show these organisms while they are lacking at another locality. You are clearly mistaken in your findings and such foolery could only be the result of an amateur. Mr. Adam Sedgwick knows extensively of my work on this matter.
Sedgwick: Yes, Roderick has spent considerable amounts of time in the greywacke and has never encountered these fossils that Henry speaks of. It is well known that the qualities of strata are continuous, regardless of their geographical placement. It is hogwash to believe that Henry’s locality would show inconsistencies. And I pray you, how can it be that you expect us to believe a man who cannot even keep his own estate and financial affairs in good working order?
de la Beche: I assure you gentlemen, and members of this congregation, that neither my personal finances, nor a babble of a mistake could erase my findings. This is true as the nose on my face. I can put your doubts to rest with but one solution. Come to my site in Devonshire and there you will be satisfied with my statement here today. There you will see that all that I say is an accurate representation of the nature of this greywacke layer.
Murchison: Not even a king concerns himself with that activities on ants in his kingdom. My time is not worth that of the likes of a man who masquerades himself as a geologist and a gentleman. No, Henry. Your drivel is not worth of my time.
The year is 1834. William IV ruled England and the Prime Minister, Charles Grey, just passed the slavery Abolition Act throughout all of the British Empire. The people of London were wearing neck ruffs, jewelled headbands through elaborate hairstyles and large sleeves hung on the end of every arm. Geology is a new science that is quickly being undertaken by gentlemen- that is, men of inherited wealth who love to travel, study the natural world, and then form societies to discuss their findings over a social dinner. William Buckland had described the first ever dinosaur fossils just ten years prior and Charles Darwin was on his legendary voyage on the HMS Beagle to South America. Some of the latest and greatest work came from William Smith, a mining surveyor that found, controversially, that fossils were effective in distinguishing stratigraphic beds that were otherwise quite similar. Scholars engaged in debates regarding just how old the Earth really was. While some new ideas were being discussed that would suggest that the world was significantly older than the bible taught, others resisted this growing trend. Geologists were keen to make some of the first geologic maps of Britain.
It was the beginning of the industrial revolution. Through the increasing use of steam power, bio-fuels and coal, humans were moving “full steam ahead” with the tremendous amount of mining and infrastructural growth. The knowledge of the geologists was suddenly needed in new and interesting ways to develop more predictive practices in construction and energy extraction. For the first time in history, there is a significant economic reliance on the Earth Sciences. New emphasis on geology is prompting the development of the most prominent societies, including the Geologic Society of London. Founded in 1807, it is the oldest society devoted specifically to Earth Sciences. Here, exists a gentlemanly code of how to go about science. Papers are presented to fellow geologists and rebuttals come in the form of future papers. Arguments are structured with mediators and all findings are published for the public to view. This society holds prestigious international regard as the most active centre of geological research, with its 745 members.
THINK [2]: What challenges might geologists at this time encounter? How are those challenges similar or different to challenges posed by geologists today?
Section 2: Character Introduction
Please proceed to Activity 1
Section 3: Course Content
Some of the most groundbreaking work is being done at this time, including the work of two geologists, Nicholas Steno and William Smith. The next part of this case will examine key principles just put forth by each of these men regarding the relative dating of stratigraphic beds
There is great debate amongst scholars and the church as to the actual age of the Earth. The Biblical interpretation of the earth emphasized a static surface. It was created as is with little or no change since the beginning. Steno, having observed stratigraphic sequences (though this is not what he would have called them) was able to reason change through time based on the relationship from one sequence to the next. His assertions were four-fold:
- Superposition…
- Original horizontality…
- Lateral continuity…
- Cross cutting relationships...
The implication of Steno’s assertions was that the rocks at the surface of the earth had changed. What was considered to be a place with no history became a story telling of rocks being laid down, eroded away, broken and tilted, etc. The earth had a history much older than many had imagined that was now becoming known to scientists. These assertions were picked up by Hutton, who read Steno's book, Dissertationis prodromus of 1669. He proposed endless cycles of mountain wasting, deposition, deformation into mountains. This happened, according to Hutton through very small changes over long periods of time. This idea became what Lyell called uniformitarianism.
The Law of Faunal Succession – William Smith
Understanding the nature of stratigraphy aided in the assignment of relative ages to stratigraphic beds, and in turn, their contained fossils. Smith worked in the coal industry in England. His role concerned the planning of manmade canals that would be used to transport coal from the countryside to urban areas. Through this process, Smith realized that certain rock layers contained certain types of fossils. The older the rock, the more primitive the fossil forms that are present. He originally used this knowledge to predict where coal could be found.
In conjunction with a French geologist, Georges Cuvier, they suggest that rocks containing similar fossils in France are the same age as those in England. Thus is born the idea that certain types of fossils exist for a specific period of time in Earth history and that the layers of rock bearing these fossils could be correlated, or equated to one another, even over great geographic distances. The Smith-Cuvier discoveries are termed the “Principle of Faunal Succession” which says that fossils and groups of fossils exist for limited amounts of time, and that fossil plants and animals appear in the rock record in a definitive pattern. Applying the Law of Superposition and the Principle of Faunal Succession led to the creation of a relative chronology of Earth history.
It is important to mention, however, that while the Law of Faunal Succession might seem logical today, during this time in history it was incredibly controversial. Smith’s principle of faunal sequence is another way of saying that there are discontinuities in the sequences of fossilized plants and animals. These discontinuities are interpreted in two ways: as indicators of episodic destruction of life or as evidence for the incompleteness of the fossil record. Scientists are still debating the actual age of the earth. Even though evidence is accumulating to suggest that the world is considerably older than the church has suggested, an alternate theory of Catastrophism is present. The discontinuities of strata is evidence for this theory, stating that instead of a slow and steady change in Earth’s environment and organisms, that at times, massive catastrophes (flood, landslides etc.) would produce rapid change, thus allowing for the age of the Earth to still be considered biblically short. Being in direct competition with Lyell’s Uniformitarianism and a very old Earth, Smith’s theory of faunal succession is being given merit at this time.
Section 4: Activity
Please proceed to Activity 2
Section 5: Return to Synopsis
At this time, two scientists (of many) were following trend of examining the stratigraphy of England. These scientists were Henry de La Beche and Roderick Murchison and their research took them to studying the same layer of strata at two different localities. They each hoped to map their own area, and then meet up with each other at a future date to complete their maps because, presumably, from the Law of Superposition, their maps should line up. Stakes are high as del Beche is working in a prestigious position for the Geological Survey and Murchison in his militant style proceeds to his designated territory. Both have a looming pressure to increase stratigraphical knowledge for the purpose of finding coal, and the income that would come with that.
Section 6: Activity
Please proceed to Activity 3
Both geologists have found a layer that has the same mineral composition of the Cambrian but the same fossils as shown in the coal measures of the Carboniferous. Murchison interprets this layer as being older, like the layer of greywacke he is comparing it to, and De La Beche dates the layer as younger, like the coal measures, because he is using William Smith’s controversial Law of Faunal Succession.
ADD TIME SCALES TO SHOW CHANGE? Clarify where to find this? predevonian and post-devonian? pg 166cambrian silurian carboniferous…. get some of the diagrams showing the bars going across and what people were thinking. data from many places and trying to make it uniform. flip through GDC book and find an appropriate example and explain their reasoning.
THINK [3]: How might you explain the presence of this anomaly?
Section 7: Return to Synopsis
Hence, the controversy is revealed! Both geologists can’t be right and both geologists have their reputations on the line. Word spread of this alleged mistake throughout the Geologic Society and general public. De la Beche receives ridicule from the scientific community because much of the community says that he must have mistook the layer he found the fossils from, which is an embarrassing rookie This is how i understood it from the book. A mistake like he had no experience mistake. De la Beche becomes the focus of scientific bullying due to such a serious, perceived inaccuracy.
He wrote the following in a letter addressed to Sedgwick shortly after presenting his findings at the Geological Society of London:
Murchison and Lyell, who confessedly never saw a square yard of the country, attacked me most fiercely, particularly the latter, declaring their perfect conviction that I had made a gross mistake as to the geological position of the beds whence the plants were derived, &c. &c. &c. Now as I toiled day after day, for months in the district, examining every hole and cranny in it, this was a pretty good go of preconceived opinions against facts, which are so plain that the merest infant in geology could make no mistake.
Murchison and Lyell, who confessedly never saw a square yard of the country, attacked me most fiercely, particularly the latter, declaring their perfect conviction that I had made a gross mistake as to the geological position of the beds whence the plants were derived, &c. &c. &c. Now as I toiled day after day, for months in the district, examining every hole and cranny in it, this was a pretty good go of preconceived opinions against facts, which are so plain that the merest infant in geology could make no mistake.
- De la Beche
Even after repeatedly inviting his critics to actually come to the site to see for themselves, no one does. To make matters worse for De la Beche, his family plantation in Jamaica, which is the source of his gentlemanly income, has stopped producing, leaving him in financial turmoil that further restricted him from traveling to the Geologic Society of London to plea his case. All of this has roused quite of bit of drama within the scientific community of England.
THINK [4]: Imagining that you were unsure of whether de la Beche’s claims were correct or not, why might you chose to travel to his locality, or not?
THINK [5]: Imagining that you were de la Beche, how would your loss of income affect your position in this debate? How does it affect your professional standing and your ability to do your work? What position would you be in if your were Murchison?
Murchison takes the data he found as representing a general rule for all of the particular strata, instead of being an exception. His stubborn reaction is explained in a letter from Sedgwick back to de la Beche:
He has, as you know, examined an astonishing fine series of upper fossiliferous Greywacke; and finding no coal plants in it, resolved in his own mind that the said plants could not be found any where else. I have once or twice argued this very point with him… This counts well enough for his reluctance to admit your facts.
Therefore, this case becomes an argument of theoretical vs. observational geology. This conflict grows within the Geological Society, members taking sides, like Sedgwick, rather surprisingly after his correspondence with de la Beche, joining forces with Murchison. The society’s president, George Greenough, initially would not go public with this debate for fear of damaging the Society’s reputation, but on his last day as in his leadership position issued the following controversial statement:
Unshackled by authority, unenslaved by preconceived opinions, unreduced by the love of novelty, free from all vanity and authorship, concise, methodical, exercising his judgement continually, his fancy seldom, the author may not obtain that popularity which with less merit he might have easily commanded; but such work cannot fail to be appreciated here.
What Greenough means by this statement is that when science is done true to its nature, results should be free from bias from authority, popularity and other social pressures. Pressures, that he was under leaving him unable to comment on the goings-on of this debate. Yet, behind closed doors and through years of field study throughout mainland Europe, de la Beche and Murchison pursued the answer to this riddle. This is when the gentlemanly code of the Society was not entirely adhered to. Knowing of de la Beche’s hardships, Murchison purposely schedules critical debates of de la Beche’s cross section interpretation at hasty times when da la Beche can not afford to get a defence together or collect more data.
Murchison eventually travels to where De la Beche collected his data, with his new team mate, Sedgwick. There, the stratigraphic anomaly threw them for a loop also, but now, after so much time had been dedicated to contradicting de la Beche, the duo pursues any other possible explanations for this inconsistency.
THINK [6]: Why might Sedgwick have chosen to take Murchison’s side on this debate?
Section 8: Conclusion
Through his means for arguing his point, Murchison loses his chief help, Sedgwick. Sedgwick became get up with Murchison’s unwillingness to practice and argue science within the gentlemanly code that was expected by the scientific community. Despite losing his ally, Murchison continues on to gather more evidence on this stratigraphical section as it was found in other locations. His field work leads him to parts of Russia, where he finds the boundaries between periods were much clearer and this filled in many of the holes that the maps of England had. After years of debate, he discovers that this cross-section belongs to a time in history not yet recognized within the geologic timescale. This period becomes known as the Devonian time period, this debate has become known as the Great Devonian Controversy. Much of the scientific community is in consensus with this explanation and largely it is not discussed much again, now that the dramatic aura of this issue has subsided. Even today, many scholars in this field are not familiar with this story, even though it was once so prominent amongst geologists and the general public alike.
THINK [7]: Murchison gained recognition for naming the Devonian, although it involved implicitly acknowledging that de la Beche was right about the fossils and the sequence of strata in Devon. Do you think Murchison’s actions throughout the controversy were ultimately justified? How do you weigh scientific and social considerations in your judgment?”
THINK[8]: How might the status and life history of these men have made their scientific view and social interactions biased? How might you have your own biases in your approach to science?
THINK [9]: Much of the original sources of material to develop this case study has come from records like letters. How might this material present biased history?
THINK [10]: Review your answer to THINK [1]. In light of the development of the Devonian system, how does this story change aspects of your understanding of the process of science?
THINK [11]: Can you think of current controversies in science? How would you apply knowledge of the outcome of the Great Devonian Controversy to inform your understanding of these current controversies
Activities
Understanding Controversy
Students receive GU1830_Bio cards and are urged to work in small groups of 3-5. They read through the cards together, and may be asked to adopt a perspective of one of these men to aid in their historical immersion.
You are now familiar with some of the leading geologists of the day. They come from different backgrounds that can end up giving these men biases in their approach to science. Have students regroup and discuss the following:
THINK [2]: This activity has brought to light a correlation with wealth and the men who did science, at this stage in history. With so much wealth, why do you think these men chose to study geology if they were not under the pressure to work a full-time job like the lay-person? How are these motivations the same and different to modern day individuals choosing their profession.
ADD TIME SCALES TO SHOW CHANGE? Clarify where to find this? predevonian and post-devonian? pg 166cambrian silurian carboniferous…. get some of the diagrams showing the bars going across and what people were thinking. data from many places and trying to make it uniform. flip through GDC book and find an appropriate example and explain their reasoning.
THINK [3]: How might you explain the presence of this anomaly?
Section 1: Setting the Stage
First part of this section is presented as a dialogue that is meant to have occurred in the Geologic Society of London. It executed best when students are assigned the role of each scientist in the dialogue and it is read out loud to the class.
In our execution of this case we found the second part of section was best delivered as a narrative read out by us with the accompaniment of slides showing various images of 1830s England. These included pictures of the dress, the industrial revolution, the Geologic Society of London and gentlemen doing their fieldwork in their hats and tails.
This section is important to set the scene so students can imagine the mentality of the scientists of the day. Make sure to mention:
- The fact that gentlemen were the ones able to practice science - for future information regarding how social status affects one’s scientific reputation later in the case.
- That scholars were in debate as to how old the Earth really was - to reinforce why scholars were unsure as to the validity of the Law of Faunal Succession later in the case.
- Geology was integral in the growing coal mining industry so was begging to be funded like never before.
Section 2 / Activity 1: Character Introduction
Print and hand out GU1830_Bio Cards to students in small groups and proceed to section Activity 1. Urge the students to work in small groups of 3-5. Have them read through the cards together. A potential suggestion moving further into the case might be to ask your students to adopt a perspective of one of these men to aid in their historical immersion. If choosing to forgo this activity, briefly overview “GU1830s_Character Bios” to develop a familiarity with the relevant characters to this case.
This section is important to reinforce the Nature of Science issue that science can be biased based on the personal history of the scientist or biased in how current researchers are able to access historical information. If struggling, students can be prompted by:
- Asking the students how each scientist came about their wealth and how they think that would affect their work.
- Asking the students how they think each scientist might value the use of fossils in determining the dating of strata or discredit the idea altogether.
Section 3: Course Content
We found that in the execution of this section, each teacher had a personal preference as to how these laws were taught. It is encouraged in this section to self direct this lesson as to your preferences.
This section is important to relay course curriculum regarding the Law of Superposition and the Law of Faunal Succession and their social relevance. Make sure to mention:
- The details of how each Law operates.
- The nature of how these laws contributed to an old Earth compared to Catastrophism.
Section 4 / Activity 2
We found in the execution of this case students showed an appropriate amount of discussion as to the possible placements of each cross-section and in almost all cases chose the desired outcome.
This section is important exercise the student’s knowledge of the curriculum in a hands on manner After completion, make sure to mention:
- That the geologists of the day discovered the same thing - to reinforce that they are going through this case the same as the gentlemen would have.
- Great changes in stratigraphy corresponds with what scientists call different time periods - to reinforce the discovery/naming of the Devonian time period at the end of this case.
Students are provided with cross-sections of stratigraphic beds and based on the Law of Superposition, are asked to relatively date each sequence. Each stratigraphic cross section represents a collection of what the geologic minds of the day collected from three localities, North Wales, the Welsh Boarderland and the Mendip Hills. To complete this activity, the cross sections are cut out in strips and placed on the provided template.
If their knowledge of the Law of Superposition is applied correctly, students should have a diagram that roughly resembles this.
They are given confirmation that that was, in fact, what the geologic minds of the day discovered also. At the time, geologists views major breaks in the stratigraphy as indications that the environment underwent massive changes. They gave names to these time periods in history, as indicated in the diagram above with the Carboniferous, Silurian and Cambrian periods.
Section 6 / Activity 3
This is the pinnacle controversy of this case and is not recommended to be overlooked. Students will experience the problem that caused the geologic upheaval just as the scientists would have. This activity leads student to believe it will work like Activity 2, but come across data as enigmatic.
Students will reconvene with their small groups. We found this moment in teaching our case the most exciting part. We found the discussion of multiple placements of the Devonshire cross-section and reactions ranging from intrigue to confusion - as planned.
Students are given another cross section of information, found by De La Beche and Murchision, and asked to place it within their template. It has the colouring (mineral composition) of the lower greywacke of the Cambrian but the same fossils as shown in the coal measures of the Carboniferous.
This becomes problematic because, hopefully, students will not know how to line it up. Do they match up the colour (the mineral composition) or the embedded fossils? Students are told that this is exactly what happened to De La Beche and Murchison too. They both interpreted their data quite differently.
Murchison finds the greywacke to be dated like this because he was correlating the greywacke strata with that of the older placement of the greywacke in North Wales.
De La Beche found his greywacke to be dated like this because he discovered fossilized flora that correlated with the younger strata found in Mendip Hills.
This section is important to introduce the major problem of this case. Make sure to:
- Allow the students to discuss and hash out their varying ideas of the placement of the Devonshire cross-section. Let them be confused as this will reinforce why the geologists of the day were arguing also
- Explain how de la Beche and Murchison came up with different interpretations of the strata because they valued the Law of Faunal Succession differently.
Section 7: Return to Synopsis
When executing this section, we chose the style of group discussion for Think Questions 4 and 5
Section 8: Conclusion
We conducted this section by means of group discussion for the Think Questions. We believe this was effective for the same reasoning as stated in Section 7 (Return to Synopsis). When answering Think Question 11, the discussing of modern controversies should remain highly moderated to focus on WHY they are controversies, instead of the emotional debate of what the controversies actually are.
References
- Clark, John Willis and Thomas McKenny Hughes, The Life and Letters of Adam Sedgwick. Cambridge: Cambridge University Press, 1890.
- Geiki, Archibald, Life of Sir Roderick Murchison… based on his journals and letter with notices of his scientific contemporaries and a sketch of the rise and growth of Palaeozoic geology in Britain. London: John Murray, 1875.
- Laudan, Rachel, “William Smith. Stratigraphy without palaeontology.” Centaurus 20 (1976): 210-26.
- Lyell, Katherine, Life letters and journals of Sir Charles Lyell. London: John Murray, 1881.
- Rudwick, Martin J.S. “Hutton and Werner compared: George Greenough’s geological tour of Scotland in 1805.” British Journal of Historical Science 1 (1962): 117-35.
- Rudwick, Martin J.S. The Great Devonian Controversy. Chicago and London: The University of Chicago Press, 1985
- Rudwick, Martin J.S. “The foundation of the Geological Society of London: Its scheme for cooperative research and its struggle for independence.” British Journal of Historical Science 1 (1963): 325-55.
- Secord, James A. “King of Siluria: Roderick Murchison and the imperial theme in nineteenth-century British geology.” Victorian Studies 25 (1982): 413-42.
- Secord, James A. Controversy in Victorian geology: The Cambrian-Silurian Dispute. Princeton: Princeton University Press, 1986.