How The Geology Of Mountains Made America Great

The story of the Appalachians started almost half a billion years ago. The first British colonialists arrived to North America just 400 years ago and yet both events are connected and shaped the history of the United States. Without a series of orogenic cycles 490-300 million years ago, caused by the continental collision assembling the super-continent Pangaea and forming the geological roots of the Appalachians, maybe today there would be the United States of Canada, bordering to the south with the Spanish-American Empire.

The first British colonialists arrived to America in 1607 and were confined by the mountains to the Atlantic coastal plains. The parallel north-south trending ridges of the Appalachians, formed by tilted and folded layers, were a difficult terrain, not suited for permanent settlements and of no use to the first farmers. 

Fig.1. Geological Map of Pennsylvania, published in 1858, showing the north-south trending ridges of the Appalachians mountains (source).

Only the French, settling from the North (territory later to become Canada), claimed the Appalachians, establishing a network of outposts for trading fur in the mountains. In the south Florida and the Great Plains were claimed by the Spanish crown as New Spain. 

It seemed that the British were surrounded by both natural as political opponents. However the isolation soon provided decisive. The plains in the Great Appalachian Valley in eastern Pennsylvania provided fertile ground and the population of the colonies grow over time, unnoticed by the French and Spanish. Soon the British expanded westwards in search of new land. This led to a conflict between England and France above the control of the few gaps and mountain passes in the Appalachians. The English colonists were far more numerous and better supplied than the French, having direct access to the sea. The rugged, poorly accessible terrain of the Appalachians proved difficult to defend by the French and allied Indians and were eventually lost to the expanding British colonies.
 

After the end of the French-American War the English crown wanted to limit the colonization and new settlements to the area of the Appalachians, hoping so to avoid further conflicts with the remaining French and Spanish territories. However the unexpected result was a resentment among the British settlers in America. Colonialists became convinced that the crown didn´t care for the political future of the successful expanding colonies. Among other factors, this resentment will contribute to the later Revolutionary War, where the American colonies will declare their independence, leading in the end to the foundation of the United States of America.
 

Bibliography:
 

ALESHIRE, P. (2008): The Extreme Earth - Mountains. Chelsea House Publishers: 144

Damned Souls and Fiery Oceans - Early Views Of Earth`s Core

"We know more about the stars high above our heads, than about earth just below our feet."
Leonardo da Vinci
 

There is some truth in da Vinci´s words, as for a long time the interior of earth was a mysterious place, supposedly the reign of demons and place of eternal damnation. Italian poet Dante Alighieri (1265-1321) imagined a core of ice, an allegoric image, far away from the sun and divine light where the damned souls are entrapped in eternal ice. 

German Jesuit Athanasius Kircher (1602–1680) imagined earth´s section in his "Mundus Subterraneus" (1664-1665) as crossed by veins of water and fire. The water would feed springs and rivers, the fire the volcanic mountains – but apart practical observations Kircher´s worldview was influenced also by religious-philosophical considerations, the two opposite elements water and fire united in a perfect creation.
 

Fig.1. from "Mundus Subterraneus", first edition published in 1664-1665.

Leonardo da Vinci´s (1452-1519) approach was more rational, even if inspired by the idea that earth worked a bit like a human body, just blood replaced by water. Water, so da Vinci, eroded, transported and deposited sediments, connecting mountains with the sea. He imagined earth filled by an immense underground ocean, sections of the superficial crust sinking into it would explain the formation of mountains.
 

Fig.2. Leonardo da Vinci´s speculative section of planet earth, from his private notes (Codex Leicester, 1510).
 

James Hutton (1726-1797) recognized the importance of magmatic rocks on earth. To explain the large quantities of volcanic rocks on earth´s surface and the energy needed to melt rocks, Plutonists proposed a molten interior, even if it is was not clear if molten rocks form most of earth or were to be found in only large magmatic chambers, distributed in the upper layers of earth.
 

Fig.3. Section of earth from Erasmus Darwin´s poetic-naturalistic work (1791), note the "unknown region supposed to consist of Lava kept in semifluid state by heat...[]".

French science-fiction author Jules Gabriel Verne (1828 - 1905) based his novel "A Journey to the Center of the Earth" (1864) on the science of his time. In his novel Verne uses the hollow conduit of the Icelandic volcano Snæfellsjökull to venture inside earth, an idea supported by the geologic models of volcanoes proposed at the time - a single or a series of magma chamber(s) with conduits connecting them to the surface. Geologists assumed that during an eruption the magma reservoir becomes empty and large voids and caverns were left behind.
 

Fig.4. Geological section, published in the book "Einführung in die Erdbeben- und Vulkankunde Süditaliens" (1914), shows the anatomy of a stratovolcano, with a main conduit, various lateral dikes and a large sill connected to the magma reservoir. 

The Spanish adaptation of Verne´s novel "The Fabulous Journey to the Center of the Earth"/ Where Time Began" (1976) summarizes best the problems geologists faced all this time:

"-Gentleman, the truth is that all our theories are just that, theories. None of us has the least idea of how the earth was really formed. Because the distance between the earths crust and its core is over 6.500 kilometres, and no men has ever descended to a depth of more than 3 miles. So it's obvious, we will never have a glimmer of true knowledge, until we are able to reach a depth of at least a 100 leagues.
 

- What's your opinion Professor Lindenbrook?
 

- Well gentlemen, at one point at least I agree with Professor Christophe, the materials of the geologists are not charts, chalk and chatter, but the earth itself. We should never know the truth, until we are able to make that journey, and see for ourselves."

To be continued...

Bibliography:
 

PARCELL, W.C. (2009): Signs and symbols in Kircher’s Mundus Subterraneus. In Rosenberg, G.D., ed., The Revolution in Geology from the Renaissance to the Enlightenment: Geological Society of America Memoir 203: 63-74

Frauds, Fakes and Fossils

“What are they?

Creations of mind?- The mind can make Substance,
and people planets of its own
With beings brighter than have been, and give
A breath to forms which can outlive all flesh”
“The Dream“, Lord Bryon (1788-1824)

In the year 1725 the professor of medicine and personal physician of the bishop of the German town of Würzburg, Dr. Johann Bartholomäus Adam Beringer (1667-1738), was approached by three chaps, who offered him the possibility to purchase some strange stones they had found in the fields.

Beringer recognized the unique value of the discovery and paid a rich reward for these and further specimens. After a short time he possessed the greatest collection of stones displaying on the surface various bugs, molluscs, plants, birds, mammals, stars, suns and even Hebraic letters.
One year later, in 1726, Beringer published a monographic work with 14 sections and 21 plates depicting 204 specimens of his collection: the “Lithographia Wirceburgensis”, assuring the veracity of the stones as a divine miracle.

But then the scandal was revealed – the chaps admitted that the stones were artificially carved, incited by two peers of Beringer, the mathematician Jean Ignace Roderique (1697-1756) and the theologian Johann Georg von Eckhardt (1664-1730). The two scholars admitted that the fraud was their revenge for the presumptuous behaviour of Beringer and intended to expose his credulity and incompetence. The public was not amused by the childish behaviour of all the involved persons: The reputation of all the three scholars was ruined, Roderique and Eckhardt were forced to leave the city and Beringer tried to minimize the damage by destroying almost all of the printed copies and the printing plates of his book. He never recovered from the humiliation and died embittered years later.
Almost every student of earth sciences knows this or a similar version of the myth, often told in textbooks as warning of blind faith and argument from authority. The beautiful carved stones of limestone are today remembered as “Würzburger Lügensteine” – the infamous “lying stones of Würzburg“.

However careful study of the still existing stones and the preserved historic documents of the lawsuit that investigated the claims of fraud at Beringer´s time depict a much more complicated “criminal case.”

Today 434 lying stones survive, 494 are depicted in the Lithographia Wirceburgensis and Beringer himself claims that he possessed more than 2.000. However considering the short period in which the “discoveries” took place (less than one year) it seems more reasonable to assume that this number is deliberately exaggerated. Estimated 600 to 1.100 true lying stones seem a more plausible number.

Beringer affirms that he received or discovered the first stones in May of the year 1725. Between June and November he hired the two brothers Hehn, the chap Zänger and later a fourth person, which name is not recorded, to collect further stones on the presumed site of the first discovery.

Beringer began almost immediately to describe the various stones and ordered the printing plates for his book; he also published a preview of his work in October of 1725. Already then first doubts were cast on the veracity of the stones, but Beringer presented various witnesses that could testify that indeed the stones were found during the excavations on a hill near Würzburg. Johann Georg von Eckhardt, and later Jean Ignace Roderique, were send to investigate the site but couldn’t find any stone there. However they also couldn’t provide evidence to dismiss Beringer´s claims.

It is important to note that Beringer never affirmed that the stones were true petrifactions (as the petrified remains of organisms killed by the biblical flood) and he even states that the stones differ from the true petrifactions found in the hills near Würzburg. He discusses in great detail the various explanations proposed for the origin of petrifactions in the first chapters of “his” Lithographia (as a matter of fact the book is published as doctoral thesis under the name of one of Beringer´s students – Georg Ludwig Hueber – but his contribution is limited to an introduction of nine pages) and examines the various hypotheses, but dismiss all in favour of a literally “miracle”. God himself created these stones and the recognizable carving spurs (!) on the stones are only a trace of the power of god creating these figures.

In spring of 1726 Beringer received some rocks from the fourth chap, this time in fact fabricated by Roderique to reveal the artificial nature of the stones. The fraud is revealed, even in the presence of the bishop (the Lithographia is dedicated to him), but Beringer simply modifies some chapters of the Lithographia, still in press, claiming that it is now only proven that the last stones are fakes and the first generation is still evidence for (literally) god’s hand carving the rocks. Beringer is apparently so self-confident in his position that he initiates a process against the claims of fraud regarding his persona. In the process, that will last until after the publication of the Lithographia, the incriminated chaps will only admit to have sold the stones to Beringer, but not to have carved the figures. Considering the depictions of exotic animals and even Hebraic letters on the lying stones it is in fact difficult to image that people from a rural area with no naturalistic background would be able to execute such an elaborate hoax.

There is no doubt that the scholar Roderique manufactured some of the stones, however he arrived to Würzburg only in the winter 1725-1726, so he can not be responsible for the first generations of stones described by Beringer already in October of 1725. Roderique left Würzburg voluntarily in 1730, the revealed “scandal” had no influence on his career and he died as respected scholar and publisher years later. There is no evidence that Eckhart played a major role in the entire story, apart the first investigation of the supposed excavation site. Both Roderique and Eckhart had no need for revenge versus Beringer and were relatively unsuccessful in the attempt to discredit the lying stones, as they – or others, could never demonstrate that that the first stones were fakes.

But who then faked the first lying stones?

Beringer didn’t suffer too much from the supposed scandal, not only didn’t he even try to prevent the publication of the Lithographia after the first claims of fraud (there was still plenty of time left), but he retained his position and reputation. In 1767 even a second edition of the Lithographia was published with the original plates (not even touched by Beringer) of the first edition.
His hypothesis of divine intervention on the rocks was never ridiculed in a time when fossils were anyway considered the vestiges of a biblical flood. However it is true that after the newspapers revealed that it was possible to fake the stones (like done by Roderique) the lying stones could no longer be used to support uncritically the "divine crafted" hypothesis.

Only after Beringer´s death his strange behaviour, he remained unimpressed by all the claims of fraud, was interpreted by many authors as simple ignorance or even criminal stubbornness. But maybe he remained calm because he was sure that nobody could definitely prove that the first generations of stones were fakes, simply because he knew who carved the figures in the stones. Beringer had the naturalistic knowledge and probably also the contacts to professional craftsmen to perpetuate such an elaborate hoax – even if we never will know the entire truth, one fact is clear, the modern myth of the lying stones is itself a lie…

Bibliography:

BEHRINGER, J.B.A. & HUEBER, G.L. (1726): Litographiae Wirceburgensis, ducentis lapidum figuratorum, a potiori insectiformium, prodigiosis imaginibus exornatae specimen. Würzburg 1726. Scan by www.BioLib.de
NIEBUHR, B. & GEYER, G. (2005): Beringers Lügensteine: 493 Corpora Delicti zwischen Dichtung und Wahrheit. Beringeria Sonderheft 5, Teil II: 188

Celebrating the Irish-Geological Heritage

According to a popular myth, long time ago lived a giant named Finn McCool on the shores of the county of Antrim in Ireland. On the opposite shores lived the Scottish giant Benandonner. One day Benandonner challenged McCool to a battle. McCool started to build a bridge, made of large columns of black rocks, to cross over the Irish Sea. Soon the bridge was completed and seeing his furious opponent approaching, Benandonner became afraid of the battle. So he asked advice to his wife. The wife responded “go hide in your bed and let me do the talking!” As McCool entered the castle, he asked astonished “who is this giant man snoring so loud in this bed?” The wife responded “Oh, it’s only our youngest, but my husband will be back soon. “ If this was the child, how big would be the father?! McCool started to run back to Ireland, destroying the bridge of columns behind him – so that’s why we today see ending the giant’s causeway in the middle of the sea.

As charming this account is, it is probably not a true myth but a story told for the first tourists visiting the site, as there is no mention of it in historic documents or collections of Irish folklore. Today the legendary formation of the “Giant’s Causeway” is understood much better. When the Antrim basalt started to cool down the crystallizing rock contracted in volume, forming joints resembling a hexagonal pattern on the surface of the former lava flow.

The first mention of the “Giant’s causeway” was published in an anonymous travel account in 1693. Travelling around the rural Irish landscape was an arduous task at the time and scholars intrigued by the first descriptions of this strange site preferred to send artists there, instructed to produce a realistic representation of the scenery. Apparently the first results were very deluding, as the scholar Reverend William Hamilton remarks in 1786:

“Neither the talents nor the fidelity of the artist seem to have been at all suited to the purpose of the philosophical landscape . . . . In this true prospect, the painter has very much indulged his own imagination…[]“

Fig.1. The first published image of the Giant’s Causeway by local artist Christopher Cole Foley was used to illustrate an account by Samuel Foley, Bishop of Down and Connor, in 1694. However both the drawing and the engraving from it were considered inadequate depictions of this peculiar Irish landscape.

The Dublin Society decided to offer an award for the most realistic and scientific accurate illustration of the Giant’s Causeway. In 1740 the prize was won by Dublin artist Susanna Drury, who spent three months along the Irish coast to study the landscape and produce two paintings (a view from the east and a view from the west) of the Giant’s Causeway. These paintings were used as reference for various later engravings and illustrations and significantly increased the interest of the people in this geologic formation, today one of the most popular landscape in Northern Ireland and designated as World Heritage site by the UNESCO in 1986.

Fig.2. An engraving of 1768 based on the original painting by Susanna Drury “East Prospect of the Giant’s Causeway”.

Bibliography:

DOUGHTY, P. (2008): How things began: the origins of geological conservation. From: BUREK, C. V. & PROSSER, C. D. (eds) The History of Geoconservation. Geological Society, London, Special Publications, 300:7-16

The Shells tell the Truth: Molluscs, some Stratigraphic Order and early Evolution

"He was painter, and he used his art to vividly depict his own concepts. So he depicts on the frontispiece the spirit of observation who, climbing on a mountain on which ground are spread marine bodies, shows one of those to a somehow surprised ghost, emerging from the mist, which seems not able to believe his own eyes."
Brocchi (1814) describing the work of his predecessor, artist and naturalist Agostino Scilla. Scilla in 1670 published “La vana speculazione disingannata dal senso”, where he argued that fossils are the petrified remains of once living beeings and one simply had to observe the similarities between the fossils and recent marine organisms in the field, instead of vain philosophising, to recognize this simple truth.

 

Fig.1. "Vanae Speculationis Sensus Moderator", a later published  (1752) Latin edition of Scilla´s work.

Italian mineralogist Gian Battista Brocchi (1772-1826) may not well known nowadays, but as both Charles Lyell as Charles R. Darwin were influenced by his works, he significantly contributed to forge modern geology.
He studied jurisprudence and theology in the Italian town of Padua, but soon became interested in geology, mineralogy, botany and zoology and will frequently combine or even merge his various interests. Brocchi, who studied also ancient Egyptian art, argued that certain cultural phases and art-styles first appeared in a rudimentary form, developed over time to become more elaborated and finally would become obsolete and replaced by other, more modern, art-styles. Strongly influenced by this observation he applied a similar approach to botany and zoology, where he compared recent species with fossil ones, noting that similar to cultural phases, also species can become extinct and are replaced over time by new ones.

Also in the mineral kingdom he observed an “evolution” of minerals over time, even more curious, he argued on a sort of “descend with modification”. In his "Trattato mineralogico e chimico sulle miniere del Dipartimento del Mella" (1807-1808) he explained the great varieties of minerals as derived from a set of more simple rocks - as he states - “evolved” slowly over time according to natural laws acting now as in the past (it´s not a coincidence that such ideas sound similar to Lyell´s later uniformitarianism).

His observations and research as inspector of mines in the recently established (1805-1814) kingdom of Italy was published in 1814 in the two volumes of “Subapennine Fossil Conchology”, where he also resumes all his geological as paleontological speculations. 

 

Fig.2. A somehow thoughtful Brocchi on the frontispiece of his book "Chonchiologia Fossile Subapennina con Osservazioni Geologiche sugli Apennini e sul suolo adiacente” (1814).

Volume one is an introduction, discussing stratigraphic as geological problems, volume 2 deals with the classification, description and distribution of Italian fossils found in Tertiary strata. Brocchi showed that different strata can be distinguished by the different species-assemblages, where the found fossil species become more and more similar to recent species as younger is the studied strata. Scottish geologist Charles Lyell, who was fluent in Italian and surely know of Brocchi´s work, will use the classification and distribution of fossil molluscs to define the geological epochs of the /former) Tertiary period. For Brocchi only the extinction of species and birth of new ones could explain the stratigraphic order he had observed. 

 

Fig.3. Fossil shells (bottom, Pliocene-Pleistocene) showing already some striking similarities to recent (top) shells of marine snails and bivavlves found along the Adriatic coast. Brocchi and later Lyell observed that with decreasing age of the geological strata more and more "recent" molluscs appeared in the sediments.

Unlike other contemporary naturalists like Comte de Buffon (1707-1788) and Georges Cuvier (1769-1832), Brocchi didn´t consider an external force (or catastrophes) necessary or responsible for the disappearance of a species from the geological record. Like a single human life or an entire culture, also a species would appear, evolve and thrive, but in the end vanish and disappear – it was inevitable and only a matter of time. Mammal species, appearing and disappearing quickly in the geological record, had a short “species-life”-expectancy. Molluscs, known for their longevity and also based on the observed stratigraphic range, had a longer life-expectancy and therefore slower faunal turnover. Brocchi surely know of Lamarck´s work on the fossil molluscs (completed in 1809) of the stratigraphic succession in the basin of Paris. Lamarck also subdivided geological strata based on fossil molluscs assemblages, but more important was an eager promoter of “variable species”. However from the contemporary reactions it seems that Lamarck´s s work was not well received. Lyell dedicated an entire volume of his "Principles of Geology" (1830) to rebut Lamarck´s hypothesis on transmuting species and Darwin considered the entire work of the French naturalist as "useless". Brocchi in contrast was at the time one of the few international recognized Italian naturalists and both Lyell´s uniformitarianism as the subdivision of the former Tertiary are based in part on Brocchi´s geological work. We know for sure that Darwin was strongly influenced by Lyell´s work and so surely came in contact with Brocchi´s geological ideas. Also some of Brocchi´s works on species evolution were translated into English and were probably discussed in lectures or in private meetings by the former teachers (like mineralogist Robert Jameson) of young Darwin.

Darwin during his voyage on the Beagle (1831-1836) wondered if species may die and are reborn in a discontinuous natural process.
Observing fossils similar to bones of the modern Mara (Dolichotis patagonum), a South American rodent that resembles a small deer, Darwin realized that species were replaced in time by similar forms. However the young Darwin didn´t yet consider a gradual transition of one species into another possible, as he frequently refers to the observed animals as “individual species” and distinct entities in time. Only some time later, influenced by Lyell´s  uniformitarianism, he will publish a more gradual model, where evolution doesn´t occur in jumps (as may suggested by Brocchi) but by slow and gradual evolution of populations. The distinct stratigraphic differences in species assemblages and the sharp limits between those, as used by Brocchi and Lyell to distinguish geological epochs, were for Darwin more an artifact caused by the"imperfection of the geological record" than by a supposed limited life-expectancy of a species. Species went extinct not for an organism-intern property, but simply because some species, by chance better suited to exploit the limited resources, would better survive and generate more offsprings and so over time replace less adapted species.

Bibliography:

CAPROTTI, E. (2010): Antiporte malacologiche del Settecento. Boll. Malacol. 46: 16-28
DOMINICI, S. & ELDREDGE, N. (2010): Brocchi, Darwin, and Transmutation: Phylogenetics and Paleontology at the Dawn of Evolutionary Biology. Evo Edu Outreach Vol.3(4): 576-584
DOMINICI, S. (2010): Brocchi’s Subapennine Fossil Conchology. Evo Edu Outreach Vol.3(4): 585-594

Eppur non si muove - Galileo Galilei and the impossible biomechanics of giants

Until the 17th century the discovery of skeletons of giants was a quite common event. In January 1546 and then in the years 1564, 1580 and 1613 bones were unearthed near the castle of Chaumont (France). The bones were identified as the bones of the giant Teutobochus, king of the barbarians, and exhibited in many French cities. Jesuit Jacques Tissot describes the discovery as follows:

“The real story of the life and the bones of the giant Teutobochus, king of the Teutons, Cimbrians and Ambrones, defeated in the year 105 before Christ. He was defeated along with his army of 100.000 men by Mario, the Roman consul, and then he was killed and buried near the castle once known as Chaumont and now as Langon, near the Roman town of Daulphiné. On this site his tomb was discovered, thirty feet long, with his name written in Roman letters. The bones in the grave exceeded 25 feet and one tooth was heavier than 11 pounds, all bones were monstrous in size and shape, as you will see in display“

Fig.1. Generations of giants, image from “Mundus subterraneus” by Athanasius Kircher (1678). The biggest giant is based on the bones discovered in Sicily, from left to right follows a common man, the legendary Goliath, the giant of Lucerne and the giant of Mauritania.

Today the supposed bones of giants are identified as fossils of extinct large ice-age mammals and gigantic reptiles known as dinosaurs. 

However already in 1638 the Italian physicist Galileo Galilei (1564-1642) realized that the basic principles of biomechanics refute the existence of human giants. In his book “Discorsi e Dimostrazioni Matematiche intorno a due nuove Scienze Attenenti alla Meccanica & i Movimenti Locali” (Discourses and Mathematical Demonstrations Relating to the Two New Sciences of Mechanics and Movements) he describes how the bones of large and small animals must differ in their proportions as a result of physical laws. A larger bone is not simply a larger copy of a small bone, but its thickness increases much faster than the length to support the increased weight of a larger body. A human giant would never show human proportions, but be a shapeless monster, unable even to move .... Eppur non si muove!

Fig.2. Figure from “Discorsi e Dimostrazioni Matematiche…” showing how thickness of a column (and bone) must increase much faster than lenght to support increased forces.

Bibliography:

Prothero, D. (2003): Bringing Fossils To Life: An Introduction To Paleobiology. McGraw-Hill Science: 512

From the Contracting Earth to early Supercontinents

“What are they? Creations of mind?- 
The mind can make Substance, and people planets of its own  
With beings brighter than have been, and give  
A breath to forms which can outlive all flesh.”
“The Dream“, Lord Byron (1788-1824)

Already when the first maps of America were published (1507 and after), geographers and naturalists alike noted the similar shape of the west-coast of Africa and the east-coast of South America.

In 1620 the English philosopher Francis Bacon claimed in his “Novum Organum” that “it’s more then a curiosity”. In 1658 the cleric Francois Placet published a small booklet entitled “The break up of large and small world’s, as being demonstrated that America was connected before the flood with the other parts of the world.” He argued that the two continents were once connected by the continent of “Atlantis”, submerged and lost forever during the biblical flood.

The idea of a flood to explain the shape of continents will remain very popular for the next 250 years.

Fig.1. Illustration from Thomas Burnet´s book “The Sacred Theory of the Earth“, published in 1684, where he tries to explain the shapes of the continents by the biblical flood. The homogenous primordial crust of earth is shattered (first drawing) releasing water from the underground. This water covers the entire planet (second drawing) and finally flows back in the fissures, leaving behind fragments of the crust that now forms the modern islands and continents (last drawing).

The great French palaeontologist Buffon in his “Les Epoques de la Nature” (1717) not only addresses the age of earth, but also speculates about a former land bridge connecting Ireland and America to explain the distribution of fossil shells found on both sides of the Atlantic Ocean.

The American president (of the Academy and College of Philadelphia) and naturalist Benjamin Franklin explained marine fossils found on mountains in a letter to French geologist Abbé J. L. Giraud-Soulavie in 1782 as follows:

“Such changes in the superficial parts of the globe seemed to me unlikely to happen if the earth were solid to the center. I therefore imagined that the internal parts might be a fluid more dense, and of greater specific gravity than any of the solids we are acquainted with, which therefore might swim in or upon that fluid. Thus the surface of the earth would be a shell, capable of being broken and disordered by the violent movements of the fluid on which it rested.“

The great German naturalist and geographer Alexander von Humboldt explored South America in 1799-1804 and observed that the similitudes between the two coastlines were not only restricted to a morphological pattern, but also to the geological features: mountain ranges that seemed to end on one continent continued on the other, the Brazilian highland is similar to the landscape of the Congo, the Amazonian basin has it’s counterpart in the lowlands of Guinea, the mountain ranges of North America are – geologically – very similar to the old European mountains and rocks in Mexico resemble those found in Ireland.

Fig.2. Columnar Jointing in the basalts of Regla, Mexico, as depicted in Alexander von Humboldts (1810) “Pittoreske Ansichten der Cordilleren und Monumente amerikanischer Völker.” (image in public domain), the accompanying text explains: “The basalts of Regla, which are presented on this copper plate, are an incontrovertible proof of this identity of forms, which is noted on the rocks of different climates. Travelled mineralogist need only to look at this drawing to recognize the basalt forms in Vivarais, in the Euganean Mountains or in the foothills of Antrim, in Ireland. The smallest coincidences observed in the European rock-pillars are also found in this group of Mexican basalts. Such a great analogy let us assume a similar principle of formation acting under all climates in various temporal epochs, the basalts covered by compact limestone and clay-slate must be of different age than those who are resting on layers of coal and boulders.”

But even Humboldt still argued that the Atlantic Ocean represents a large and ancient river bed, flooded subsequently by the biblical catastrophe.

The French zoologist Jean-Baptiste Lamarck developed a surprisingly new hypothesis. To explain the discovery of fossil marine animals on dry land he proposed that the continents “move” slowly around the globe in a very peculiar manner. The eastern coastlines of the single continents are eroded by the sea, but in the same time new sediments were deposited on the western coasts, so the continents apparently move around the globe and the sea becomes land.
Unfortunately, also for the lack of evidence for his theory, Lamarck was not able to find a publisher for his “Hydrogéologie” and printed in 1802 on his own behalf 1.025 copies, but only a small number of books were sold.

In the early 19th century another hypothesis was proposed to explain the shape of Earth: the Contracting Earth theory formulated by the American geologist James Dwigth Dana explained mountains and continents as products of a cooling and subsequently shrinking earth. Like an old and dry apple the shrinking surface of earth would develop fissures (basins) and wrinkles (mountains).

Austrian Geologist Eduard Suess published in his multi-volume work “Das Antlitz der Erde” (1883-1909) this hand coloured map, showing the supposed remains of the primordial continents – preserved “cores of crust” surrounded by younger basins today filled with oceans. Curiously he suggested also that the deep-sea trenches, found along the borders of the Pacific, are zones where the ocean floor was pushed under the continents (!).

Fig.3. Hand coloured map showing the primordial continent -”cores” according to the Austrian geologist Eduard Suess, published in “Das Antlitz der Erde” (The Face of the Earth) 1883 to 1909 (image in public domain).

But the Contracting Earth theory couldn’t explain the irregular distribution of mountains on earth and why there are regions with strong tectonic movements and earthquakes and also “quiet” areas. According to this theory, such features and events should to be distributed randomly on the surface of a homogenous cooling and shrinking planet.

Already in 1858 the French naturalist Antonio Snider-Pellegrini (1802–1885) published a reconstruction of America and Africa forming a single continent on a planet with a fixed volume. But Snider-Pellegrini couldn’t propose a convincing mechanism, apart the great flood described in the Bible, to explain the forces needed to move entire continents.

Fig.4. This 1858 reconstruction by Antonio Snider-Pellegrini is the first map showing a former supercontinent.

Bibliography:

FRISCH, W.; MESCHEDE, M. & BLAKEY, R. (2011): Plate Tectonics – Continental Drift and Mountain Building. Springer-Publisher: 212
MILLER, R. & ATWATER, T. (1983): Continents in Collision. Time-life books, Amsterdam: 176

Nicolas Steno and the Origin of Fossils

In October 1666 a large shark was captured by a French fishing boat in the sea of Livorno (today Italy, at the time County of Tuscany), pulled onto the shore, the animal was beaten to death and dismembered, as the body was quite too heavy to be transported and only the head was saved. In Florence the Danish anatomist and naturalist Niels Stensen or latinized Nicolas Steno (born January 11, 1638) was asked to dissect this head. 

Stensen observed various anatomical particularities: the skin was covered by glands, secreting a reddish slime. Steno assumed that this slime would keep the skin smooth, helping the animal to move in water (today the ampullae of Lorenzini are considered part of an organ to sense electromagnetic fields). He noted also the structure of the brain, arguing that it appeared quite too small to coordinate such a large animal, so also the spine must have some role in (unconscious) movements (like reflexes). Finally Steno studied the mouth, noting the ranks of sharp teeth.
 

Steno, after the anatomical description, adds a chapter comparing these teeth with common fossils - the Glossopetrae or tongue stones. It´s important to note that Steno was not the first to speculate over the organic origin of such fossils, already in 1616 the Italian Fabio Colonna (1567-1640) explained glossopetrae as shark teeth. However many naturalist argued that the organic origin of fossils could not explain how such remains of sea animals  could become entrapped in rocks, found on dry land and even high in the mountains. 

Fig.1. Recent, mummified shark head.
 

But Steno was for the first time able to explain why these fossilized teeth were found inside rocks, far distant to the modern sea.  Steno had already observed fossils hosted in the Royal Danish Kunstkammer (Copenhagen) and in a private note he writes "Snails, shells, oysters, fish, etc., found petrified on places far remote from the sea. Either they have remained there after an ancient flood or because the bed of the seas has slowly been changed. On the change of the surface of the earth I plan a book, etc."
 

Fig.2. Steno's figure of a dissected shark head, comparing the teeth of a modern shark to the fossil Glossopetrae, from "Elementorum myologiæ specimen, seu musculi descriptio geometrica : cui accedunt Canis Carchariæ dissectum caput, et dissectus piscis ex Canum genere" (1667).
 

He also studied outcrops of layered rocks in Tuscany, recognizing the sedimentary origin and a stratigraphic order. However only with the description of the shark head he combines all his observations in one "geo-theory":

• Fossils, resembling modern animals, are not found in recent soils of dry land. If fossils were of inorganic nature, however we should find them in every kind of soil and rocks.
• The layering was formed by sedimentary deposition, the soil where fossils are found once was therefore a sort of liquid mud, so that bodies of dying animals could become imbedded into it
• Those soils were deposited and therefore covered once by water, this explains why fossils resemble animals of the sea
• The sea can become repeatedly dry land by movements and disturbances of earth´s crust , the fossils in the mud are uplifted, the mud dries and becomes hard soil, therefore fossils can be found high in the mountains

However Steno's work, like the work of many others before him, was ignored for decades. Then a certain John Woodward, considered an amateur physician and naturalist by some, by others a quack, used/stole the principles formulated by Steno in his 1695 book "An Essay toward a Natural History of the Earth". The best part of work, thought to support the idea of the biblical sin flood as origin of the fossils, were the text passages copied from Steno.
However the book of Woodward and the principles of Steno used in it initiated a new interest in the study of sedimentary rocks.

Bibliography:

KARDEL, T. & MAQUET, P. (eds.) (2013): Nicolaus Steno - Biography and Original Papers of a 17th Century Scientist. Springer Publishing: 739

A tribute to the Year of Crystallography - Haüy´s Models

"It would be good if the readers, who wish to follow the details of these demonstrations, make themselves or have made, in cardboard or any other materials, solids that represent the principal varieties of crystals"
Haüy, 1784 - Portrait of French naturalist Haüy with contact goniometer, an instrument to measure the crystal angles. Haüy refused to use any other type of gioniometer during his lifetime, even if after 1809 high-accuracy optical goniometers, using reflection of light to measure the angles, were introduced.

The Danish anatomist and naturalist Nicolas Steno (1638-1686) was the first to note in 1669 that the faces of a crystal (2014 was also dedicated to the science of crystals) are always arranged in specific angles and crystals display a characteristic symmetry. Mineralogist René-Just Haüy (1743-1822) used a mechanical or contact goniometer to accurate measure the angles between the faces, realizing that all the various shapes of crystals could be reduced to just a limited number of basic geometrical shapes. In 1784 he published his observations in the book" Eassai d´une théorie sur las structures des crystaux", introducing the idea of seven basic unit cells. From a single "forme primitive" (the first unit cell) by adding other unit cells a crystal could grow (this concept predates also the modern theory of crystal nucleation).

Fig.1. Haüy´s seven unit cells, note the numbering, from "Eassai d´une théorie sur las structures des crystaux" (1784).

 

Fig.2. & 3. Wooden crystal model based on Haüy´s work, made in 1805 in Paris. As certain symmetries are repeated in crystals of a mineral, Haüy concluded that a mineral is made up by smaller, basic chemical units - he called them "molecule intergrante" - symbolized here by the small cubes, forming both a larger cube as a rhombus (both characteristic shapes of the cubic crystal system). More than 500-1000 wooden models were made after 1801, some sets commissioned by Haüy himself. Most models show simple crystals with smooth faces, only 20 complex models, showing the structure with the unit cells, survive.

 

Haüy´s work was quite influential for later mineral classification. In his popular book "Über die oryktognostische Classification nebst Versuchen eines auf blossen äußeren Kennzeichen gegründeten Mineraliensystems" (The genetic-geological classification and an attempt to introduce a mineral-system based on superficial properties, published 1804) the German mineralogist Carl Friedrich Christian Mohs (1773-1839) combines various physical properties of minerals (like color, hardness and density) with crystal models to identify 183 different minerals. 
From there the use of simplified crystal geometry to identify minerals was quickly adopted by other naturalists and the classification of crystals based on the seven unit cells / crystal systems of Haüy is still in use today.

Fig.4. Carl Linnaeus "Systema Naturae", published in 1770, in his work Linnaeus didn´t not only classify animals and plants, but also minerals. One element used to identify minerals were the various crystal shapes, here still displaying a confusing variability.

Newton's Alchemy and early Geochemistry

Sir Isaac Newton (1642-1727) is today remembered for his contributions to optics, mechanics and gravity, but as a typical polymath of his time he was also interested in alchemy. And through his interest in this early predecessor of chemistry he became also involved in some geological research.

The theologian and naturalist Thomas Burnet submitted an early draft of his "Telluris theoria sacra" to Newton in 1680-1681 and Newton exchanged with Burnet some thoughts on the formation of the rocks, mountains and the earth. Based on his observations of crystallization of molten tin and saltpeter from water, but also curdling of milk when beer is added to it, Newton imagined earth's matter somehow crystallizing from the primordial, undifferentiated chaos.

Newton never published in full his geological ideas - but some surviving notes deal with (early) geochemical concepts. Two notes, dated to 1670, entitled "Of Natures Obvious Laws & Processes in Vegetation" and "Humores mineralis" deal with the "sal nitrum" theory.  The crystallization of saltpeter, or potassium nitrate (KNO3), is easily observable both in nature as in the laboratory and it was considered by many naturalist of Newton's time as ideal model to understand mineral growth and finally the genesis of ore veins in mountains. 

Alchemy regarded saltpeter even as a sort of philosopher's stone, able to transform into other minerals.

Fig.1. "The Alchymist, In Search of the Philosopher’s Stone, Discovers Phosphorus, and prays for the successful Conclusion of his operation, as was the custom of the Ancient Chymical Astrologers", by Joseph Wright of Derby (1771).

This transformation could explain why minerals were abundant on earth, despite the perpetual dissolution by groundwater percolating into the underground, Newton explains in "Humores mineralis":

"with the metals continually drawn downwards, never ascending so long as they remain metals, it would be necessary that in a few years the greatest part would have vanished from the upper earth, unless they are conceded to be generated there de novo."

The term "vegetation" in the title of Newton's other note refers to the idea of a spontaneous force generating new metals in the centre of earth and injecting them into earth's crust - alchemy considered principles influencing the inorganic nature very similar (or even identical) to life processes. It's therefore no wonder that Newton describes fluids and vapours ("spirits") mating in earth's crust to give birth to the progenitors of metals:

"Indeed, these spirits meet with metallic solutions and will mix with them. And when they are in a state of motion and vegetation, they will putrefy [and] destroy the metallic form and convert [it] into spirits similar to themselves. Which can then ascend again and thus a perpetual circulation of metals takes place."

These progenitors derived from saltpeter, especially sulphur and mercury as most important elements in alchemy, will continue to migrate to the surface, where they transform and are deposited as other useful metals. Such metaphysical explanations for the origin of rocks will prevail for a long time in history.

Bibliography:

NEWMAN W.R. (2009): Geochemical concepts in Isaac Newton's early alchemy. In Rosenberg, G.D., ed., The Revolution in Geology from the Renaissance to the Enlightenment. Geological Society of America Memoir 203: 41-49

Invasion of the European Dinosaurs!! Part I: ca. 1800-1900

Fig.1. Archaeopteryx  

The fossil gallery at the recent Munich Show 2011 was dedicated to the "European Dinosaurs" - a good overview of some of the historic fossils (with the classics from Victorian Britain and Germany), but also special apparitions of the newest discoveries from the Mesozoic of the European continent.

Dinosaurs have a long tradition in Europe - the first (as such) recognized "terrible lizards" came from England: it was in 1824 that there Reverend William Buckland described the lower jaw of Megalosaurus. 

Fig.2. The jaw of Megalosaurus as published in Buckland´s "Notice on the Megalosaurus or great Fossil Lizard of Stonesfield" (1824).

Fig.3. Isolated tooth, Megalosaurus bucklandi, from the Jurassic Stonesfield-Formation (Oxfordshire), found previously of 1882.

But already in 1677 the English historian Robert Plot (1640-1696) describes in his "The natural history of Oxfordshire" a gigantic bone (today lost), found presumably in a quarry at Chipping Norton (also Oxfordshire), as the bone of an elephant of Roman age.
It seems plausible that in the next centuries ulterior bones were discovered, however only with the advent of comparative anatomy (promoted by the French naturalist Georges Cuvier) it became clear what these bones could be - the remains of large reptiles, however quite different to all living animals. After the description of Megalosaurus soon followed Iguanodon (1825), Hyaeosaurus (1833), Thecodontosaurus (1836) and Cetiosaurus (1836).

The first non-british dinosaur came from the Triassic sediments of Southern Germany, described by the German palaeontologist Hermann von Meyer as Plateosaurus in 1837. 

 Fig.5. Plateosaurus.

Streptospondylus and Poekilopleuron were described in 1832 and respectively in 1838 from Jurassic sediments in France. Archaeopteryx was first described (again by von Meyer) in 1861 based on a single feather, only later an almost complete specimen started an intense debate about the evolutionary connection between dinosaurs and birds. In the same year a distant cousin of Archaeopteryx was described by Andreas Wagner as a sort of very strange lizard: Compsognathus longipes.

Fig.6. The first fossil of Compsognathus, discovered in 1858 by physicist and fossil collector Joseph Oberndorfer.

The British anatomist Thomas Henry Huxley recognized it as example of one of the first complete dinosaurs and based his very cautionary and speculative hypothesis of a possible "relationship" between reptiles and birds on this species. Huxley described in 1868 another small dinosaur species, but this time a herbivore: Hypsilophodon.
In February 1878 miners discovered a bone bed of Iguanodon, the almost complete skeletons enabled palaeontologist Louis Dollo (1857-1931) to reconstruct a large, biped and herbivorous animal. 

Fig.7. Hypsilophodon foxii, Wealden (Lower Cretaceous), collected previously 1882.

Bibliography:

RAUHUT, O.W.M. (2011): Kontinent der Dinosaurier - Europa. Mineralientage München - Messekatalog: 132-146