Editing Continental drift

{{Short description|Movement of Earth's continents relative to each other}}
{{About|the development of the continental drift theory before 1958|the contemporary theory|Plate tectonics|other uses|Continental Drift (disambiguation)}}
{{Distinguish|Continental drip}}
{{Use dmy dates|date=May 2024}}

'''Continental drift''' is a highly supported [[scientific theory]], originating in the early 20th century, that [[Earth]]'s [[continent]]s move or drift relative to each other over [[Geology|geologic]] time.<ref name="pubs.usgs.gov" /> The theory of continental drift has since been validated and incorporated into the science of [[plate tectonics]], which studies the movement of the continents as they ride on plates of the Earth's [[lithosphere]].<ref name="Oreskes-2002" />

The speculation that continents might have "drifted" was first put forward by [[Abraham Ortelius]] in 1596. A pioneer of the modern view of mobilism was the Austrian geologist [[Otto Ampferer]].<ref>Kalliope Verbund: ''[https://kalliope-verbund.info/de/eac?eac.id=116302275 Ampferer, Otto (1875–1947) ]''</ref><ref>Helmut W. Flügel: ''[https://www2.uibk.ac.at/downloads/c715/geoalp_1_04/01fluegel.pdf Die virtuelle Welt des Otto Ampferer und die Realität seiner Zeit]''. In: Geo. Alp., Vol. 1, 2004.</ref> The concept was independently and more fully developed by [[Alfred Wegener]] in his 1915 publication, <nowiki/>"The Origin of Continents and Oceans".<ref name="Wegener-1912" /> However, at that time his hypothesis was rejected by many for lack of any motive mechanism{{explain|reason="Motive mechanism" is an academic term that the general reader may not understand.|date=January 2025}}. In 1931, the English geologist [[Arthur Holmes]] proposed [[mantle convection]] for that mechanism.

== History ==
{{Further|Timeline of the development of tectonophysics (before 1954)}}

=== Early history ===
{{See also|Early modern Netherlandish cartography|l1=Early modern Netherlandish cartography and geography}}
[[File:Abraham Ortelius by Peter Paul Rubens.jpg|left|thumb|upright=1.1|[[Abraham Ortelius]] by [[Peter Paul Rubens]], 1633]]

[[Abraham Ortelius]] {{Harv|Ortelius|1596}},<ref name="Romm-1994" /> Theodor Christoph Lilienthal (1756),<ref name="Schmeling-2004" /> [[Alexander von Humboldt]] (1801 and 1845),<ref name="Schmeling-2004" /> [[Antonio Snider-Pellegrini]] {{Harv|Snider-Pellegrini|1858}}, and others had noted earlier that the shapes of [[continent]]s on opposite sides of the [[Atlantic Ocean]] (most notably, Africa and South America) seem to fit together.<ref name="Brusatte-2016" /> W. J. Kious described Ortelius's thoughts in this way:<ref name="Kious-2001" />
{{blockquote|Abraham Ortelius in his work Thesaurus Geographicus ... suggested that the Americas were "torn away from Europe and Africa ... by earthquakes and floods" and went on to say: "The vestiges of the rupture reveal themselves if someone brings forward a map of the world and considers carefully the coasts of the three [continents]."}}

In 1889, [[Alfred Russel Wallace]] remarked, "It was formerly a very general belief, even amongst geologists, that the great features of the earth's surface, no less than the smaller ones, were subject to continual mutations, and that during the course of known geological time the continents and great oceans had, again and again, changed places with each other."<ref name="Wallace-1889" /> He quotes [[Charles Lyell]] as saying, "Continents, therefore, although permanent for whole geological epochs, shift their positions entirely in the course of ages."<ref name="Lyell-1872" /> and claims that the first to throw doubt on this was [[James Dwight Dana]] in 1849.

[[File:Antonio Snider-Pellegrini Opening of the Atlantic.jpg|right|thumb|upright=1.4|[[Antonio Snider-Pellegrini]]'s Illustration of the closed and opened [[Atlantic Ocean]] (1858)<ref name="Snider-Pellegrini-1858" />]]

In his ''Manual of Geology'' (1863), Dana wrote, "The continents and oceans had their general outline or form defined in earliest time. This has been proved with regard to North America from the position and distribution of the first beds of the [[Lower Silurian]], – those of the [[Potsdam Sandstone|Potsdam epoch]]. The facts indicate that the continent of North America had its surface near tide-level, part above and part below it (p.196); and this will probably be proved to be the condition in Primordial time of the other continents also. And, if the outlines of the continents were marked out, it follows that the outlines of the oceans were no less so".<ref name="Dana-1863" /> Dana was enormously influential in America—his ''Manual of Mineralogy'' is still in print in revised form—and the theory became known as the ''Permanence theory''.<ref name="Oreskes-2002-2" />

This appeared to be confirmed by the exploration of the deep sea beds conducted by the [[Challenger expedition|''Challenger'' expedition]], 1872–1876, which showed that contrary to expectation, land debris brought down by rivers to the ocean is deposited comparatively close to the shore on what is now known as the [[continental shelf]]. This suggested that the oceans were a permanent feature of the Earth's surface, rather than them having "changed places" with the continents.<ref name="Wallace-1889" />

[[Eduard Suess]] had proposed a supercontinent [[Gondwana]] in 1885<ref name="Suess-1885" /> and the [[Tethys Ocean]] in 1893,<ref name="Suess-1893" /> assuming a [[Land bridge#Land bridge theory|land-bridge]] between the present continents submerged in the form of a [[geosyncline]], and [[John Perry (engineer)|John Perry]] had written an 1895 paper proposing that the Earth's interior was fluid, and disagreeing with [[Lord Kelvin]] on the age of the Earth.<ref name="Perry-1895" />

=== Wegener and his predecessors ===
[[File:Alfred Wegener 1910.jpg|left|thumb|upright=.75|Alfred Wegener]]

Apart from the earlier speculations mentioned above, the idea that the American continents had once formed a single landmass with Eurasia and Africa was postulated by several scientists before [[Alfred Wegener]]'s 1912 paper.<ref name="Wegener-1912" /> Although Wegener's theory was formed independently and was more complete than those of his predecessors, Wegener later credited a number of past authors with similar ideas:<ref name="Wegener-1966" /><ref name="Wegener-1929" /> Franklin Coxworthy (between 1848 and 1890),<ref name="Coxworthy-1924" /> [[Roberto Mantovani]] (between 1889 and 1909), [[William Henry Pickering]] (1907)<ref name="Pickering-1907" /> and [[Frank Bursley Taylor]] (1908).<ref name="Taylor-1910" />

The similarity of southern continent geological formations had led [[Roberto Mantovani]] to conjecture in 1889 and 1909 that all the continents had once been joined into a [[supercontinent]]; Wegener noted the similarity of Mantovani's and his own maps of the former positions of the southern continents. In Mantovani's conjecture, this continent broke due to [[Volcanism|volcanic]] activity caused by [[thermal expansion]], and the new continents drifted away from each other because of further expansion of the rip-zones, where the oceans now lie. This led Mantovani to propose a now-discredited [[Expanding Earth theory]].<ref name="Mantovani-1889" /><ref name="Mantovani-1909" /><ref name="Scalera-2003" />

Continental drift without expansion was proposed by [[Frank Bursley Taylor]],<ref name="Lane-1944" /> who suggested in 1908 (published in 1910) that the continents were moved into their present positions by a process of "continental creep",<ref name="Taylor-1910a" /><ref name="Frankel-2012" /> later proposing a mechanism of increased tidal forces during the [[Cretaceous]] dragging the crust towards the equator. He was the first to realize that one of the effects of continental motion would be the formation of mountains, attributing the formation of the Himalayas to the collision between the [[Indian subcontinent]] with Asia.<ref name="Powell-2015" /> Wegener said that of all those theories, Taylor's had the most similarities to his own. For a time in the mid-20th century, the theory of continental drift was referred to as the "Taylor-Wegener hypothesis".<ref name="Lane-1944" /><ref name="Powell-2015" /><ref name="Hansen" /><ref name="Wood-2016" />

Alfred Wegener first presented his hypothesis to the German Geological Society on 6 January 1912.<ref name="Wegener-1912" /> He proposed that the continents had once formed a single landmass, called [[Pangaea]], before breaking apart and drifting to their present locations.<ref name="Wegenerproofs">{{cite web |url = http://www.bbm.me.uk/portsdown/PH_061_History_b.htm |title = Wegener and his proofs |archive-url=https://web.archive.org/web/20060505053619/http://www.bbm.me.uk/portsdown/PH_061_History_b.htm |archive-date=5 May 2006 |url-status=dead}}</ref>

Wegener was the first to use the phrase "continental drift" (1912, 1915)<ref name="Wegener-1912" /><ref name="Wegener-1966" /> ({{langx|de|"die Verschiebung der Kontinente"}}) and to publish the hypothesis that the continents had somehow "drifted" apart. Although he presented much evidence for continental drift, he was unable to provide a convincing explanation for the physical processes which might have caused this drift. He suggested that the continents had been pulled apart by the [[Centrifugal force (fictitious)|centrifugal pseudoforce]] ({{lang|de|Polflucht}}) of the Earth's rotation or by a small component of astronomical [[precession]], but calculations showed that the force was not sufficient.<ref name="PlateTectonics-2011" /> The {{lang|de|[[Polflucht]]}} hypothesis was also studied by [[Paul Sophus Epstein]] in 1920 and found to be implausible.

=== Rejection of Wegener's theory, 1910s–1950s ===
Although now accepted, and even with a minority of scientific proponents over the decades, the theory of continental drift was largely rejected for many years, with evidence in its favor considered insufficient. One problem was that a plausible driving force was missing.<ref name="pubs.usgs.gov" /> A second problem was that Wegener's estimate of the speed of continental motion, {{cvt|250|cm/y|round=10}}, was implausibly high.<ref name="UniCalifMusPaleontology" /> (The currently accepted rate for the separation of the Americas from Europe and Africa is about {{cvt|2.5|cm/y|0}}.)<ref name="Unavco-2015" /> Furthermore, Wegener was treated less seriously because he was not a geologist. Even today, the details of the forces propelling the plates are poorly understood.<ref name="pubs.usgs.gov" />

The English geologist [[Arthur Holmes]] championed the theory of continental drift at a time when it was deeply unfashionable. He proposed in 1931 that the Earth's mantle contained convection cells which dissipated heat produced by radioactive decay and moved the crust at the surface.<ref name="Holmes-1931" /> His ''Principles of Physical Geology'', ending with a chapter on continental drift, was published in 1944.<ref name="Holmes-1944" />

Geological maps of the time showed huge [[land bridge]]s spanning the Atlantic and Indian oceans to account for the similarities of fauna and flora and the divisions of the Asian continent in the Permian period, but failing to account for glaciation in India, Australia and South Africa.<ref name="Wells-1931" />

====The fixists====
[[Hans Stille]] and [[Leopold Kober]] opposed the idea of continental drift and worked on a "fixist"<ref name="Sen30" /> [[geosyncline]] model with [[Contracting Earth|Earth contraction]] playing a key role in the formation of [[orogen]]s.<ref name="Sen28" /><ref name="Sen29" /> Other geologists who opposed continental drift were [[Bailey Willis]], [[Charles Schuchert]], Rollin Chamberlin, Walther Bucher and [[Walther Penck]].<ref name="Sen31" /><ref name="Bremer-1983">{{Cite journal|title=Albrecht Penck (1858–1945) and Walther Penck (1888–1923), two German geomorphologists|journal=[[Zeitschrift für Geomorphologie]]|last=Bremer|first=Hanna|volume=27|pages=129–138|issue=2|year=1983|doi=10.1127/zfg/27/1983/129|bibcode=1983ZGm....27..129B}}</ref> In 1939 an international geological conference was held in [[Frankfurt]].<ref name="Frankel403" /> This conference came to be dominated by the fixists, especially as those geologists specializing in tectonics were all fixists except Willem van der Gracht.<ref name="Frankel403" /> Criticism of continental drift and mobilism was abundant at the conference not only from tectonicists but also from sedimentological (Nölke), paleontological (Nölke), mechanical (Lehmann) and oceanographic ([[Carl Troll|Troll]], [[Georg Wüst|Wüst]]) perspectives.<ref name="Frankel403" /><ref name="Frankel405" /> [[Hans Cloos]], the organizer of the conference, was also a fixist<ref name="Frankel403" /> who together with Troll held the view that excepting the [[Pacific Ocean]] continents were not radically different from oceans in their behaviour.<ref name="Frankel405" /> The mobilist theory of [[Émile Argand]] for the [[Alpine orogeny]] was criticized by Kurt Leuchs.<ref name="Frankel403" /> The few drifters and mobilists at the conference appealed to [[biogeography]] (Kirsch, Wittmann), [[paleoclimatology]] ([[Kurt Wegener|Wegener, K]]), [[paleontology]] (Gerth) and [[geodesy|geodetic]] measurements (Wegener, K).<ref name="Frankel407" /> F. Bernauer correctly equated [[Southern Peninsula (Iceland)|Reykjanes]] in south-west [[Iceland]] with the [[Mid-Atlantic Ridge]], arguing with this that the floor of the Atlantic Ocean was undergoing [[extensional tectonics|extension]] just like Reykjanes. Bernauer thought this extension had drifted the continents only {{cvt|100-200|km|round=10}} apart, the approximate width of the [[Volcanism of Iceland|volcanic zone in Iceland]].<ref name="Frankel409" />

[[David Attenborough]], who attended university in the second half of the 1940s, recounted an incident illustrating its lack of acceptance then: "I once asked one of my lecturers why he was not talking to us about continental drift and I was told, sneeringly, that if I could prove there was a force that could move continents, then he might think about it. The idea was moonshine, I was informed."<ref name="McKie-2012" />

As late as 1953—just five years before [[Samuel Warren Carey|Carey]]<ref name="Carey-1958" /> introduced the theory of [[plate tectonics]]—the theory of continental drift was rejected by the physicist Scheidegger on the following grounds.<ref name="Scheidegger-1953" />
* First, it had been shown that floating masses on a rotating [[geoid]] would [[Polflucht|collect at the equator]], and stay there.  This would explain one, but only one, mountain building episode between any pair of continents; it failed to account for earlier [[Orogeny|orogenic]] episodes.
* Second, masses floating freely in a fluid substratum, like icebergs in the ocean, should be in [[Isostasy|isostatic]] equilibrium (in which the forces of gravity and buoyancy are in balance). But gravitational measurements showed that many areas are not in isostatic equilibrium.
* Third, there was the problem of why some parts of the Earth's surface (crust) should have solidified while other parts were still fluid. Various attempts to explain this foundered on other difficulties.

=== Road to acceptance ===
{{Main|Plate tectonics}}

From the 1930s to the late 1950s, works by [[Felix Andries Vening Meinesz|Vening-Meinesz]], Holmes, [[Johannes Herman Frederik Umbgrove|Umbgrove]], and numerous others outlined concepts that were close or nearly identical to modern plate tectonics theory.  In particular, the English geologist Arthur Holmes proposed in 1920 that plate junctions might lie beneath the [[sea]], and in 1928 that convection currents within the mantle might be the driving force.<ref name="Holmes-1928" /> Holmes's views were particularly influential: in his bestselling textbook, ''Principles of Physical Geology,'' he included a chapter on continental drift, proposing that Earth's [[Mantle (geology)|mantle]] contained [[convection cell]]s which dissipated [[radioactive]] heat and moved the crust at the surface.<ref name="Wessel-2007" /><ref name="Vine-1966" /> Holmes's proposal resolved the phase disequilibrium objection (the underlying fluid was kept from solidifying by radioactive heating from the core). However, scientific communication in the 1930s and 1940s was inhibited by [[World War II]], and the theory still required work to avoid foundering on the [[orogeny]] and [[isostasy]] objections. Worse, the most viable forms of the theory predicted the existence of convection cell boundaries reaching deep into the Earth, that had yet to be observed.{{citation needed|date=May 2018}}

In 1947, a team of scientists led by [[Maurice Ewing]] confirmed the existence of a rise in the central Atlantic Ocean, and found that the floor of the seabed beneath the sediments was chemically and physically different from continental crust.<ref name="Lippsett-2001" /><ref name="Lippsett-2006" /> As oceanographers continued to [[Bathymetry|bathymeter]] the ocean basins, a system of mid-oceanic ridges was detected. An important conclusion was that along this system, new ocean floor was being created, which led to the concept of the "[[Great Global Rift]]".<ref name="Heezen-1960" />

Meanwhile, scientists began recognizing odd magnetic variations across the ocean floor using devices developed during World War II to detect submarines.<ref name="LATimes-2009" /> Over the next decade, it became increasingly clear that the magnetization patterns were not anomalies, as had been originally supposed. In a series of papers published between 1959 and 1963, Heezen, Dietz, Hess, Mason, Vine, Matthews, and [[Lawrence Morley|Morley]] collectively realized that the magnetization of the ocean floor formed extensive, zebra-like patterns: one stripe would exhibit normal polarity and the adjoining stripes reversed polarity.<ref name="Mason-1961" /><ref name="Korgen-1995" /><ref name="Spiess-2003" /> The best explanation was the "conveyor belt" or [[Vine–Matthews–Morley hypothesis]]. New [[magma]] from deep within the Earth rises easily through these weak zones and eventually erupts along the crest of the ridges to create new oceanic crust. The new crust is magnetized by the Earth's magnetic field, which undergoes [[Geomagnetic reversal|occasional reversals]]. Formation of new crust then displaces the magnetized crust apart, akin to a conveyor belt – hence the name.<ref name="Heirtzler-1966" />

Without workable alternatives to explain the stripes, geophysicists were forced to conclude that Holmes had been right: ocean rifts were sites of perpetual orogeny at the boundaries of convection cells.<ref name="LePichon-1968" /><ref name="McKenzie-1967" /> By 1967, barely two decades after discovery of the mid-oceanic rifts, and a decade after discovery of the striping, plate tectonics had become axiomatic to modern geophysics.

In addition, [[Marie Tharp]], in collaboration with [[Bruce Heezen]], who was initially sceptical of Tharp's observations that her maps confirmed continental drift theory, provided essential corroboration, using her skills in cartography and seismographic data, to confirm the theory.<ref name="Barton-2002" /><ref name="Blakemore-2016" /><ref name="Evans-2002" /><ref name="Doel-2006" /><ref name="Wills-2016" />

====Modern evidence====
Geophysicist [[Jack Oliver (scientist)|Jack Oliver]] is credited with providing seismologic evidence supporting plate tectonics which encompassed and superseded continental drift with the article "Seismology and the New Global Tectonics", published in 1968, using data collected from seismologic stations, including those he set up in the South Pacific.<ref name="NYTimes-2011" /><ref name="Isacks-1968" /> The modern theory of [[plate tectonics]], refining Wegener, explains that there are two kinds of crust of different composition: [[continental crust]] and [[oceanic crust]], both floating above a much deeper "[[Plasticity (physics)|plastic]]" mantle. Continental crust is inherently lighter. Oceanic crust is created at [[Seafloor spreading|spreading centers]], and this, along with [[subduction]], drives the system of plates in a chaotic manner, resulting in continuous [[orogeny]] and areas of isostatic imbalance.

[[File:Mesosaurus.png|thumb|''Mesosaurus'' skeleton, MacGregor, 1908]]

[[File:Snider-Pellegrini Wegener fossil map.svg|thumb|upright=1.5|Fossil patterns across continents ([[Gondwanaland]]) ]]

Evidence for the movement of continents on tectonic plates is now extensive. Similar plant and animal [[fossil]]s are found around the shores of different continents, suggesting that they were once joined. The fossils of ''[[Mesosaurus]]'', a freshwater reptile rather like a small crocodile, found both in [[Brazil]] and [[South Africa]], are one example; another is the discovery of fossils of the land [[reptile]] ''[[Lystrosaurus]]'' in [[Rock (geology)|rocks]] of the same age at locations in [[Africa]], [[India]], and [[Antarctica]].<ref name="USGS" /> There is also living evidence, with the same animals being found on two continents. Some [[earthworm]] families (such as Ocnerodrilidae, Acanthodrilidae, Octochaetidae) are found in South America and Africa.

The complementary arrangement of the facing sides of South America and Africa is an obvious and temporary coincidence. In millions of years, [[slab pull]], [[ridge-push]], and other forces of [[tectonophysics]] will further separate and rotate those two continents. It was that temporary feature that inspired Wegener to study what he defined as continental drift although he did not live to see his hypothesis generally accepted.

The widespread distribution of [[Permo-Carboniferous]] glacial sediments in South America, Africa, Madagascar, Arabia, India, Antarctica and Australia was one of the major pieces of evidence for the theory of continental drift. The continuity of glaciers, inferred from oriented [[glacial striation]]s and deposits called [[tillite]]s, suggested the existence of the supercontinent of [[Gondwana]], which became a central element of the concept of continental drift. Striations indicated glacial flow away from the equator and toward the poles, based on continents' current positions and orientations, and supported the idea that the southern continents had previously been in dramatically different locations that were contiguous with one another.<ref name="Wegener-1966" />
====GPS evidence====
In measuring continental drift with GPS relative to some other locations whose positions were measured by GPS, a GPS device located in Maui, Hawaii moved about 48 cm latitudinally and about 84 cm longitudinally during a time of 14 years.<ref>A HOMEPAGE SECTION dated September 2, 2014 by DJUBLONSKOPF titled: "How Do We Know The Continents Are Moving?" at the address: https://www.djublonskopf.com/2014/09/02/how-do-we-know-the-continents-are-moving/</ref>
== See also ==
* {{annotated link|Geological history of Earth}}
* [[Israel C. White]]

== Citations ==
{{reflist|refs=
<ref name="pubs.usgs.gov">{{cite web|url=http://pubs.usgs.gov/gip/dynamic/historical.html|title=Historical perspective [This Dynamic Earth, USGS]|publisher=United States Geological Survey|access-date=29 January 2008|archive-url=https://web.archive.org/web/20180727100546/https://pubs.usgs.gov/gip/dynamic/historical.html|archive-date=27 July 2018|url-status=live}}</ref>
<ref name="Schmeling-2004">{{Cite web |first=Harro |last=Schmeling |url=http://www.geophysik.uni-frankfurt.de/~schmelin/skripte/Geodynn1-kap1-2-S1-S22-2004.pdf |title=Geodynamik |year=2004 |publisher=University of Frankfurt |language=de}}</ref>
<ref name="Wallace-1889">{{citation|first=Alfred Russel|last=Wallace|title=Darwinism …|year=1889|chapter=12|publisher=Macmillan|page=341|chapter-url=https://books.google.com/books?id=0S4aAAAAYAAJ&pg=PA341}}</ref>
<ref name="Wegener-1912">{{Citation|last=Wegener|first=Alfred|title=Die Herausbildung der Grossformen der Erdrinde (Kontinente und Ozeane), auf geophysikalischer Grundlage|date=6 January 1912|url=http://epic.awi.de/Publications/Polarforsch2005_1_3.pdf|postscript=.|archive-url=https://web.archive.org/web/20111004001150/http://epic.awi.de/Publications/Polarforsch2005_1_3.pdf|url-status=dead|journal=Petermanns Geographische Mitteilungen|volume=63|pages=185–195, 253–256, 305–309|archive-date=4 October 2011}}</ref>
<ref name="Wegener-1966">{{Citation | author=Wegener, A. | title = The Origin of Continents and Oceans |orig-year=1929|year=1966 |publisher=Courier Dover Publications|isbn=978-0-486-61708-4}}</ref>
<ref name="Lane-1944">{{citation|jstor=20023483|title=Frank Bursley Taylor (1860–1938)|journal=Proceedings of the American Academy of Arts and Sciences|volume=75|issue=6|pages=176–178|last1=Lane|first1=A. C.|year=1944}}</ref>
<ref name="Powell-2015">{{cite book |last=Powell |first=James Lawrence |date=2015 |title=Four Revolutions in the Earth Sciences: From Heresy to Truth |url=https://books.google.com/books?id=fX6SBQAAQBAJ&pg=PA70 |publisher=Columbia University Press |pages=69–70 |access-date=20 October 2015 |isbn=978-0-231-53845-9 |archive-url=https://web.archive.org/web/20160603181049/https://books.google.com/books?id=fX6SBQAAQBAJ&pg=PA70 |archive-date=3 June 2016 |url-status=live}}</ref>
<ref name="Sen30">[[#Sengor1982|Şengör (1982)]], p. 30</ref>
<ref name="Sen28">[[#Sengor1982|Şengör (1982)]], p. 28</ref>
<ref name="Sen29">[[#Sengor1982|Şengör (1982)]], p. 29</ref>
<ref name="Sen31">[[#Sengor1982|Şengör (1982)]], p. 31</ref>
<ref name="Frankel403">[[#Frankel|Frankel (2012)]], p. 403</ref>
<ref name="Frankel405">[[#Frankel|Frankel (2012)]], p. 405</ref>
<ref name="Frankel407">[[#Frankel|Frankel (2012)]], p. 407</ref>
<ref name="Frankel409">[[#Frankel|Frankel (2012)]], p. 409</ref>
<ref name="Snider-Pellegrini-1858">Antonio Snider-Pellegrini, ''La Création et ses mystères dévoilés'' (Creation and its mysteries revealed) (Paris, France: Frank et Dentu, 1858), [https://archive.org/details/bub_gb_8NxWUiDuZJcC/page/n340 <!-- pg=314 --> plates 9 and 10] {{Webarchive|url=https://web.archive.org/web/20170205021404/https://books.google.com/books?id=UZdKmF3iEdUC&pg=PA314-IA3 |date=5 February 2017}} (between pages 314 and 315).</ref>
<ref name="Oreskes-2002">{{Harvnb|Oreskes|2002|p=324}}.</ref>
<ref name="Romm-1994">{{Citation |last=Romm |first=James |title=A New Forerunner for Continental Drift |journal=Nature |date=3 February 1994 |volume=367 |pages=407–408 |doi=10.1038/367407a0 |postscript=. |issue=6462|bibcode = 1994Natur.367..407R |s2cid=4281585}}</ref>
<ref name="Brusatte-2016">{{Citation |url=https://www.lib.uchicago.edu/e/crerar/crerar-prize/2003%2004%20Brusatte.pdf |title=Continents Adrift and Sea-Floors Spreading: The Revolution of Plate Tectonics |first=Stephen |last=Brusatte |access-date=16 May 2016 |archive-url=https://web.archive.org/web/20160303182900/http://www.lib.uchicago.edu/e/crerar/crerar-prize/2003%2004%20Brusatte.pdf |archive-date=3 March 2016 |url-status=live}}</ref>
<ref name="Kious-2001">{{Citation |last1=Kious |first1=W. J. |last2=Tilling |first2=R. I. |title=This Dynamic Earth: the Story of Plate Tectonics |orig-year=1996 |url=http://pubs.usgs.gov/gip/dynamic/dynamic.html |access-date=29 January 2008 |edition=Online |publisher=United States Geological Survey |isbn=978-0-16-048220-5 |chapter=Historical perspective |chapter-url=http://pubs.usgs.gov/gip/dynamic/historical.html |date=February 2001 |archive-url=https://web.archive.org/web/20110408212926/http://pubs.usgs.gov/gip/dynamic/dynamic.html |archive-date=8 April 2011 |url-status=live}}</ref>
<ref name="Lyell-1872">{{citation|first=Charles|last=Lyell|title=Principles of Geology ...|year=1872|edition=11|publisher=John Murray|page=258|url=https://archive.org/stream/principlesgeolo41lyelgoog#page/n287/mode/1up/|access-date=16 February 2015|archive-url=https://web.archive.org/web/20160406143142/https://archive.org/stream/principlesgeolo41lyelgoog#page/n287/mode/1up/|archive-date=6 April 2016|url-status=live}}</ref>
<ref name="Dana-1863">{{citation|first=James D.|last=Dana|title=Manual of Geology|year=1863|publisher=Theodore Bliss & Co, Philadelphia|page=732|url=https://books.google.com/books?id=cKJVHih77X0C&pg=PA732|access-date=16 February 2015|archive-url=https://web.archive.org/web/20150515103528/https://books.google.com/books?id=cKJVHih77X0C&pg=PA732|archive-date=15 May 2015|url-status=live}}</ref>
<ref name="Oreskes-2002-2">{{harvnb|Oreskes|2002}}</ref>
<ref name="Suess-1885">Eduard Suess, ''Das Antlitz der Erde'' (The Face of the Earth), vol. 1 (Leipzig, (Germany): G. Freytag, 1885), [http://babel.hathitrust.org/cgi/pt?id=mdp.39015048893047;view=1up;seq=792 page 768.] From p. 768: ''"Wir nennen es Gondwána-Land, nach der gemeinsamen alten Gondwána-Flora, ... "'' (We name it Gondwána-Land, after the common ancient flora of Gondwána ... )</ref>
<ref name="Suess-1893">Edward Suess (March 1893) [https://books.google.com/books?id=yQUVAAAAYAAJ&pg=PA180 "Are ocean depths permanent?"] {{Webarchive|url=https://web.archive.org/web/20170205023611/https://books.google.com/books?id=yQUVAAAAYAAJ&pg=PA180|date=5 February 2017}}, ''Natural Science: A Monthly Review of Scientific Progress'' (London), '''2''' : 180- 187. From page 183: "This ocean we designate by the name "Tethys", after the sister and consort of Oceanus. The latest successor of the Tethyan Sea is the present Mediterranean."</ref>
<ref name="Perry-1895">Perry, John (1895) "On the age of the earth", ''Nature'', '''51''' : [http://babel.hathitrust.org/cgi/pt?id=mdp.39015038750868;view=1up;seq=266 224–227] {{Webarchive|url=https://archive.today/20150217234720/http://babel.hathitrust.org/cgi/pt?id=mdp.39015038750868;view=1up;seq=266|date=17 February 2015}}, 341–342, 582–585.</ref>
<ref name="Wegener-1929">{{Citation | author=Wegener, A. | title = Die Entstehung der Kontinente und Ozeane|edition= 4 | year=1929 |publisher=Friedrich Vieweg & Sohn Akt. Ges.| place=Braunschweig| title-link = :s:de:Die Entstehung der Kontinente und Ozeane}}</ref>
<ref name="Coxworthy-1924">{{cite book|last1=Coxworthy|first1=Franklin|title=Electrical Condition; Or, How and where Our Earth was Created|date=1924|publisher=J.S. Phillips|url=https://books.google.com/books?id=STj7PAAACAAJ|access-date=6 December 2014}}</ref>
<ref name="Pickering-1907">{{Citation | author=Pickering, W.H| title = The Place of Origin of the Moon – The Volcani Problems | journal= Popular Astronomy | volume = 15 | pages=274–287| year=1907 | bibcode=1907PA.....15..274P}}</ref>
<ref name="Taylor-1910">Frank Bursley Taylor (3 June 1910) [http://babel.hathitrust.org/cgi/pt?id=njp.32101080758822;view=1up;seq=207 "Bearing of the Tertiary mountain belt on the origin of the earth's plan"], ''Bulletin of the Geological Society of America'', '''21''' : 179–226.</ref>
<ref name="Mantovani-1889">{{Citation | author=Mantovani, R.| title = Les fractures de l'écorce terrestre et la théorie de Laplace | journal= Bull. Soc. Sc. Et Arts Réunion | pages=41–53| year=1889}}</ref>
<ref name="Mantovani-1909">{{Citation | author=Mantovani, R.| title = L'Antarctide |journal= Je M'instruis. La Science Pour Tous |volume=38 | pages=595–597| year=1909}}</ref>
<ref name="Scalera-2003">{{Citation | author=Scalera, G. | chapter=Roberto Mantovani an Italian defender of the continental drift and planetary expansion |editor1=Scalera, G. |editor2=Jacob, K.-H. |title =Why expanding Earth? – A book in honour of O.C. Hilgenberg | year=2003 | place=Rome | publisher= National Institute of Geophysics and Volcanology |pages= 71–74| hdl =2122/2017}}</ref>
<ref name="Taylor-1910a">{{Citation | author=Taylor, F.B. | title = Bearing of the tertiary mountain belt on the origin of the earth's plan | journal= GSA Bulletin | volume=21 |issue=2| pages=179–226| year=1910 | doi= 10.1130/GSAB-21-179| archive-url=https://web.archive.org/web/20180601200620/ftp://rock.geosociety.org/pub/GSAToday/gt0507.pdf| url=ftp://rock.geosociety.org/pub/GSAToday/gt0507.pdf|url-status=dead | bibcode = 1910GSAB...21..179T| archive-date = 1 June 2018 }}</ref>
<ref name="Frankel-2012">Henry R. Frankel, "Wegener and Taylor develop their theories of continental drift", in ''The Continental Drift Controversy'' Volume 1: ''Wegener and the Early Debate'', pp. 38–80, Cambridge University Press, 2012. {{ISBN|9780521875042}} {{doi|10.1017/CBO9780511842368.004}}</ref>
<ref name="Hansen">Hansen, L. T., ''Some considerations of, and additions to the Taylor-Wegener hypothesis of continental displacement'', Los Angeles, 1946. {{OCLC|1247437 OCLC}}</ref>
<ref name="Wood-2016">R. M. Wood, [https://books.google.com/books?id=3TO4uTA30NAC&pg=PA254 Coming Apart at the Seams] {{Webarchive|url=https://web.archive.org/web/20160514222416/https://books.google.com/books?id=3TO4uTA30NAC&pg=PA254 |date=14 May 2016}}, ''New Scientist'', 24 January 1980</ref>
<ref name="PlateTectonics-2011">{{cite web |url=http://www.ucmp.berkeley.edu/geology/techist.html |title=Plate Tectonics: The Rocky History of an Idea |quote=Wegener's inability to provide an adequate explanation of the forces responsible for continental drift and the prevailing belief that the earth was solid and immovable resulted in the scientific dismissal of his theories. |access-date=23 August 2006 |archive-url=https://web.archive.org/web/20110411031414/http://www.ucmp.berkeley.edu/geology/techist.html |archive-date=11 April 2011 |url-status=dead}}</ref>
<ref name="UniCalifMusPaleontology">University of California Museum of Paleontology, [http://www.ucmp.berkeley.edu/history/wegener.html Alfred Wegener (1880–1930)] {{Webarchive|url=https://web.archive.org/web/20171208011353/http://www.ucmp.berkeley.edu/history/wegener.html |date=8 December 2017}} (accessed 30 April 2015).</ref>
<ref name="Unavco-2015">Unavco [http://www.unavco.org/software/geodetic-utilities/plate-motion-calculator/plate-motion-calculator.html Plate Motion Calculator] {{Webarchive|url=https://web.archive.org/web/20150425002611/http://www.unavco.org/software/geodetic-utilities/plate-motion-calculator/plate-motion-calculator.html |date=25 April 2015}} (accessed 30 April 2015).</ref>
<ref name="Holmes-1931">{{cite journal|title=Radioactivity and Earth Movements|first=Arthur|last=Holmes|author-link=Arthur Holmes|journal=Transactions of the Geological Society of Glasgow|volume=18|issue=3|year=1931|pages=559–606|url=http://www.mantleplumes.org/WebDocuments/Holmes1931.pdf|doi=10.1144/transglas.18.3.559|s2cid=122872384|access-date=15 January 2014|archive-url=https://web.archive.org/web/20191009101823/http://www.mantleplumes.org/WebDocuments/Holmes1931.pdf|archive-date=9 October 2019|url-status=live}}</ref>
<ref name="Holmes-1944">{{Cite book |last=Holmes |first=Arthur |author-link= Arthur Holmes|title=Principles of Physical Geology |edition=1st |place=Edinburgh |publisher=Thomas Nelson & Sons |year=1944 |isbn=978-0-17-448020-4}}</ref>
<ref name="Wells-1931">See map based on the work of the American paleontologist [[Charles Schuchert]] in {{citation|title=The Science of life|first1=H. G.|last1=Wells|first2=Julian|last2=Huxley|first3=G. P.|last3=Wells|year=1931|page=445|url=https://archive.org/details/in.ernet.dli.2015.221951/page/n465/mode/2up}}</ref>
<ref name="McKie-2012">{{cite news |title=David Attenborough: force of nature |first=Robin |last=McKie |url=https://www.theguardian.com/tv-and-radio/2012/oct/26/richard-attenborough-climate-global-arctic-environment |newspaper=[[The Observer]] |location=London |date=28 October 2012 |access-date=29 October 2012 |archive-url=https://web.archive.org/web/20131031164253/http://www.theguardian.com/tv-and-radio/2012/oct/26/richard-attenborough-climate-global-arctic-environment |archive-date=31 October 2013 |url-status=live}}</ref>
<ref name="Carey-1958">{{Cite news |last1=Carey |first1=S. W. |year=1958|editor1-last=Carey |editor1-first=S. W. |title=Continental Drift—A symposium |publisher=Univ. of Tasmania |place=Hobart |pages=177–363}}</ref>
<ref name="Scheidegger-1953">{{citation|last= Scheidegger |first=Adrian E. |title=Examination of the physics of theories of orogenesis |journal=GSA Bulletin |year=1953|volume= 64|issue=2 |pages= 127–150 |doi=10.1130/0016-7606(1953)64[127:EOTPOT]2.0.CO;2|bibcode = 1953GSAB...64..127S}}</ref>
<ref name="Holmes-1928">{{cite journal |last=Holmes |first=Arthur |year=1928 |title=Radioactivity and Earth movements |journal=Transactions of the Geological Society of Glasgow |volume=18 |issue=3 |pages=559–606|doi=10.1144/transglas.18.3.559 |s2cid=122872384}}; see also {{cite book |last=Holmes |first=Arthur |author-link= Arthur Holmes|year=1978 |title=Principles of Physical Geology |edition=3 |publisher=Wiley |pages=640–41 |isbn=978-0-471-07251-5}} and {{cite journal |title=Arthur Holmes and continental drift |last=Frankel |first=Henry |journal=The British Journal for the History of Science |volume=11 |issue=2 |date=July 1978 |pages=130–50 |jstor=4025726 |doi=10.1017/S0007087400016551|s2cid=145405854 }}.</ref>
<ref name="Wessel-2007">{{citation |last1=Wessel |first1=P. |last2=Müller |first2=R. D. |year=2007 |chapter=Plate Tectonics |title=Treatise on Geophysics |publisher=Elsevier |volume=6 |pages=49–98}}</ref>
<ref name="Vine-1966">{{Cite journal | last1 = Vine | first1 = F. J. | title = Spreading of the Ocean Floor: New Evidence | doi = 10.1126/science.154.3755.1405 | journal = Science | volume = 154 | issue = 3755 | pages = 1405–1415 | year = 1966 | pmid = 17821553|bibcode = 1966Sci...154.1405V | s2cid = 44362406}}</ref>
<ref name="Lippsett-2001">{{cite journal |last=Lippsett |first=Laurence |url=http://www.columbia.edu/cu/alumni/Magazine/Winter2001/ewing.html |title=Maurice Ewing and the Lamont–Doherty Earth Observatory |journal=Living Legacies |year=2001 |access-date=4 March 2008 |archive-url=https://web.archive.org/web/20180112030533/http://www.columbia.edu/cu/alumni/Magazine/Winter2001/ewing.html |archive-date=12 January 2018 |url-status=live}}</ref>
<ref name="Lippsett-2006">{{cite book |last=Lippsett |first=Laurence |chapter-url=https://books.google.com/books?id=l1os3mwQkxYC&pg=PR9|chapter=Maurice Ewing and the Lamont–Doherty Earth Observatory |editor=William Theodore De Bary |editor2=Jerry Kisslinger |editor3=Tom Mathewson |title=Living Legacies at Columbia |year=2006 |access-date=22 June 2010|isbn=978-0-231-13884-0|pages=277–97 |publisher=Columbia University Press}}</ref>
<ref name="Heezen-1960">{{cite journal |last=Heezen |first=B. |year=1960 |title=The rift in the ocean floor |journal=[[Scientific American]] |volume=203 |pages=98–110 |doi=10.1038/scientificamerican1060-98 |issue=4|bibcode=1960SciAm.203d..98H}}</ref>
<ref name="LATimes-2009">{{citation|url=http://www.latimes.com/news/science/la-me-vacquier24-2009jan24,0,3328591.story|journal=Los Angeles Times|title=Victor Vacquier Sr., 1907–2009: Geophysicist was a master of magnetics|date=24 January 2009|page=B24|access-date=20 May 2018|archive-url=https://web.archive.org/web/20140108214147/http://www.latimes.com/news/science/la-me-vacquier24-2009jan24,0,3328591.story|archive-date=8 January 2014|url-status=live}}.</ref>
<ref name="Mason-1961">{{cite journal |last1=Mason |first1=Ronald G. |last2=Raff |first2=Arthur D. |year=1961 |title=Magnetic survey off the west coast of the United States between 32°N latitude and 42°N latitude |journal=Bulletin of the Geological Society of America |volume=72 |pages=1259–66|doi=10.1130/0016-7606(1961)72[1259:MSOTWC]2.0.CO;2 |issn=0016-7606|issue=8|bibcode= 1961GSAB...72.1259M}}</ref>
<ref name="Korgen-1995">{{cite journal |last=Korgen |first=Ben J. |year=1995 |title=A voice from the past: John Lyman and the plate tectonics story |journal=Oceanography |volume=8 |issue=1 |pages=19–20 |doi=10.5670/oceanog.1995.29 |doi-access=free }}</ref>
<ref name="Spiess-2003">{{cite journal |last1=Spiess |first1=Fred |last2=Kuperman |first2=William |year=2003 |title=The Marine Physical Laboratory at Scripps |journal=Oceanography |volume=16 |issue=3 |pages=45–54 |doi=10.5670/oceanog.2003.30 |doi-access=free }}</ref>
<ref name="Heirtzler-1966">See summary in {{cite journal |last1=Heirtzler |first1=James R. |first2=Xavier |last2=Le Pichon |first3=J. Gregory |last3=Baron |year=1966 |title=Magnetic anomalies over the Reykjanes Ridge |journal=Deep-Sea Research |volume=13 |issue=3 |pages=427–32 |doi=10.1016/0011-7471(66)91078-3 |bibcode= 1966DSRA...13..427H}}</ref>
<ref name="LePichon-1968">{{cite journal |last=Le Pichon |first=Xavier |date=15 June 1968 |title=Sea-floor spreading and continental drift |journal=Journal of Geophysical Research |volume=73 |issue= 12 |pages=3661–97 |doi=10.1029/JB073i012p03661 |bibcode=1968JGR....73.3661L}}</ref>
<ref name="McKenzie-1967">{{cite journal |last1=Mc Kenzie |first1=D. |last2=Parker |first2=R.L. |year=1967 |title=The North Pacific: an example of tectonics on a sphere |journal=Nature |volume=216 |pages=1276–1280 |doi=10.1038/2161276a0 |issue=5122 |bibcode= 1967Natur.216.1276M|s2cid=4193218}}</ref>
<ref name="Barton-2002">{{cite journal | last1 = Barton | first1 = Cathy | year = 2002 | title = Marie Tharp, oceanographic cartographer, and her contributions to the revolution in the Earth sciences | bibcode = 2002GSLSP.192..215B | journal = Geological Society, London, Special Publications | volume = 192 | issue = 1| pages = 215–228 | doi = 10.1144/gsl.sp.2002.192.01.11 | s2cid = 131340403}}</ref>
<ref name="Blakemore-2016">Blakemore, Erin (30 August 2016). "Seeing Is Believing: How Marie Tharp Changed Geology Forever". Smithsonian.</ref>
<ref name="Evans-2002">Evans, R. (November 2002). "Plumbing Depths to Reach New Heights". Retrieved 2 June 2008.</ref>
<ref name="Doel-2006">{{cite journal | last1 = Doel | first1 = R.E. | last2 = Levin | first2 = T.J. | last3 = Marker | first3 = M.K. | year = 2006 | title = Extending modern cartography to the ocean depths: military patronage, Cold War priorities, and the Heezen-Tharp mapping project, 1952–1959 | journal = Journal of Historical Geography | volume = 32 | issue = 3| pages = 605–626 | doi = 10.1016/j.jhg.2005.10.011}}</ref>
<ref name="Wills-2016">Wills, Matthew (8 October 2016). "The Mother of Ocean Floor Cartography". JSTOR. Retrieved 14 October 2016. While working with the North Atlantic data, she noted what must have been a rift between high undersea mountains. This suggested earthquake activity, which then [was] only associated with [the] fringe theory of continental drift. Heezen infamously dismissed his assistant's idea as "girl talk." But she was right, and her thinking helped to vindicate Alfred Wegener's 1912 theory of moving continents. Yet Tharp's name isn't on any of the key papers that Heezen and others published about plate tectonics between 1959 and 1963, which brought this once-controversial idea to the mainstream of earth sciences.</ref>
<ref name="NYTimes-2011">{{cite news|date=12 January 2011|title=Jack Oliver, Who Proved Continental Drift, Dies at 87|page=A16|work=The New York Times|url=https://www.nytimes.com/2011/01/12/science/earth/12oliver.html|url-status=live|access-date=6 June 2013|archive-url=https://web.archive.org/web/20130526135459/http://www.nytimes.com/2011/01/12/science/earth/12oliver.html|archive-date=26 May 2013}}</ref>
<ref name="Isacks-1968">{{cite journal|last1=Isacks|first1=Bryan|last2=Oliver|first2=Jack|last3=Sykes|first3=Lynn R.|date=15 September 1968|title=Seismology and the New Global Tectonics|journal=[[Journal of Geophysical Research]]|volume=73|issue=18|pages=5855–5899|bibcode=1968JGR....73.5855I|doi=10.1029/JB073i018p05855}}</ref>
<ref name="USGS">{{Cite web |url=http://pubs.usgs.gov/gip/dynamic/continents.html |publisher=United States Geological Survey |title=Rejoined continents [This Dynamic Earth, USGS] |access-date=22 July 2010 |archive-url=https://web.archive.org/web/20100825180951/http://pubs.usgs.gov/gip/dynamic/continents.html |archive-date=25 August 2010 |url-status=live}}</ref>
}}

== General and cited sources ==
* {{Cite book |last=Frankel |first=Henry R.|date=2012 |title=The Continental Drift Controversy |volume=I: ''Wegener and the Early Debate'' |publisher=Cambridge |ref=Frankel }}
* {{Cite book |first=Homer Eugene |last=Le Grand |year=1988 |title=Drifting Continents and Shifting Theories |publisher=Cambridge University |isbn=978-0-521-31105-2 |ref=none |url-access=registration |url=https://archive.org/details/driftingcontinen00legr }}
* {{Cite book |first=Naomi |last=Oreskes |author-link=Naomi Oreskes |year=1999 |title=The Rejection of Continental Drift |publisher=Oxford University Press |isbn= 978-0-19-511732-5 |url=https://books.google.com/books?id=EEQdk9GRfkoC&pg=PA14 |ref=none}} (pb: {{ISBNT | 0-19-511733-6 }})
* {{Cite encyclopedia |first1=Naomi |last1=Oreskes |title=Continental Drift |url=http://historyweb.ucsd.edu/oreskes/Papers/Continentaldrift2002.pdf |url-status=dead |archive-url=https://web.archive.org/web/20120204234030/http://historyweb.ucsd.edu/oreskes/Papers/Continentaldrift2002.pdf |editor1-first=Ted |editor1-last=Munn |editor2-first=Michael C. |editor2-last=MacCracken |editor3-first=John S. |editor3-last=Perry |date=2002 |encyclopedia=Encyclopedia of Global Environmental Change |volume=1 |pages=321–325 |publisher=John Wiley & Sons |place=Chichester, West Sussex |isbn=978-0-471-97796-4 |oclc=633880622 |archive-date=4 February 2012 }} <!-- CAUTION: catalogs are inconsistent. This is from the printed book. -->
* {{Cite book |first=Abraham |last=Ortelius |year=1596 |orig-year=1570 |title=Thesaurus Geographicus |place=Antwerp |publisher=Plantin |language=la |edition=3 |oclc=214324616}} (First edition published 1570, [https://books.google.com/books?id=YG1EAAAAcAAJ&pg=PR4 1587 edition online])
* {{Cite book |last=Şengör |first=Celâl|author-link=Celâl Şengör |date=1982|chapter=Classical theories of orogenesis|editor-last=Miyashiro|editor-first=Akiho|editor-link=Akiho Miyashiro|editor-last2=Aki|editor-first2=Keiiti|editor-last3=Şengör|editor-first3=Celâl |title=Orogeny |publisher=John Wiley & Sons |isbn=978-0-471-103769|ref=Sengor1982}}
* {{Cite book |first=Antonio |last=Snider-Pellegrini |year=1858 |title=La Création et ses mystères dévoilés |publisher=Frank and Dentu |place=Paris |url=https://books.google.com/books?id=UZdKmF3iEdUC&pg=PA314-IA3}}.

== External links ==
{{Library resources box}}
{{Wikibooks|Historical Geology|Continental drift}}
* [http://www.age-of-the-sage.org/tectonic_plates/boundaries_boundary_types.html#franklin_emerson_continental_drift Benjamin Franklin (1782) and Ralph Waldo Emerson (1834) noted Continental Drift]
* [http://www.ux1.eiu.edu/~cfjps/1300/cont_drift.html A brief introduction to Plate Tectonics, based on the work of Alfred Wegener]
* [https://www.nytimes.com/2021/02/06/science/tectonic-plates-continental-drift.html Animation of continental drift for last 1 billion years]
* [http://www.scotese.com/earth.htm Maps of continental drift, from the Precambrian to the future]
* [https://dinosaurpictures.org/ancient-earth 3D visualization of what did Earth look like from  750 million years ago to present (at present location of your choice)]

{{Authority control}}

{{DEFAULTSORT:Continental Drift theory}}
[[Category:Obsolete geology theories]]
[[Category:Plate tectonics]]