In a night, or in a day,
In a vision, or in none,
Is it therefore the less gone?
All that we see or seem
Is but a dream within a dream."
"A Dream Within A Dream" by Edgar Allan Poe (1809-1849)
There is lot fuzz about the discovery of a slab of granite embedded into basaltic rocks of the oceanic crust - granite is a rock typical of continental crust (including island arcs), which prompted journalists to claim the discovery of a sunken continent (and no, dear journalists, granite is not formed on dry land, as plutonic rocks crystallize in the underground). Already Alfred Wegener demonstrated that continents can't simply sink, as granite has a lower mass density (2,7g/cc) it will "float" on the denser mantle materials (3g/cc).
However in past centuries lost continents were at least a geological possibility.
In the 19th century naturalists realized that many similar animals were distributed on different continents or remote islands. For short distances this was explainable by (voluntary or involuntarily) migration across the sea by "hopping" from island to island, but many distances were too great for large terrestrial animals, especially for mammals.
The British lawyer and zoologist Philip Lutley Sclater (1829-1913) noted the particular distribution of a particular group of primates - the Lemurs. Sclater however included in his Lemuridae more species than modern zoologists - the Lemurs, the Indri and the Aye-aye (found on Madagascar and shown above in a figure from SCLATER 1899), the Galagos (found in Africa), the Loris (found in Asia) and the Tarsiers (found in Indonesia). He observed that "while 30 different species of Lemurs are found in Madagascar alone, all of Africa contains some 11 or 12, while the Indian region has only 3." In a short essay of 1864 titled "The Mammals of Madagascar", published in the "The Quarterly Journal of Science", he provided a possible answer - Madagascar, with it's rich diversity of species, was the primordial homeland of lemurs which spread all over Asia and Africa by a land bridge connecting once these continents - he speculated even on a connection to America. He named this supposed land bridge/continent appropriately "Lemuria".
"The anomalies of the Mammal fauna of Madagascar can best be explained by supposing that anterior to the existence of Africa in its present shape, a large continent occupied parts of the Atlantic and Indian Oceans stretching out towards (what is now) America to the west, and to India and its islands on the east; that this continent was broken up into islands, of which some have became amalgamated with the present continent of Africa, and some, possibly, with what is now Asia; and that in Madagascar and the Mascarene Islands we have existing relics of this great continent, for which as the original focus of the "Stirps Lemurum," I should propose the name Lemuria!"
In later works he was more cautious:
"This fact would seem to show that the ancient "Lemuria", as the hypothetical continent which was originally the home of the Lemurs has been termed, must have extended across the Indian Ocean and the Indian Peninsula to the further side of the Bay of Bengal and over the great islands of the Indian Archipelago."
SCLATER & SCLATER (1899): "The Geography of Mammals."
Sclater was not the first to promote ancient land bridges or even a sunken continent in the Indian Ocean, as the idea of oceans as drown landmasses was a plausible geological theory at the time.
The French geologist Etienne Geoffrey Saint-Hilaire had speculated about a connection between Madagascar and India in 1840, the English geologist Searles V. Wood (1830-1884) hypothesized the existence of a giant southern continent during the "secondary era" (our Mesozoic). Alfred R. Wallace (1823-1913) proposed in 1859 a sunken continent to explain the fauna found on the island of Celebes, but became later one of the most eloquent critics of the theory of sunken landmasses.
In 1868 the German biologist Ernst Haeckel published his "Natrliche Schpfungsgeschichte" (The history of Creation), addressed to a general public where he promoted his view of evolution. Haeckel considered the earliest humans descending from Asian primates and placed the cradle of humanity in Asia, Africa and very cautiously on the hypothetical island between these two continents. Lemuria played a major role as possible migration route of humans into Africa and Indonesia.
In later editions and the English version of the book, translated by Ray Lankester in 1876, the supposed continent is even emphasised and labelled in the map as "Paradise" and displayed as cradle of humanity.
"The primeval home, or the "Centre of Creation", of the Malays must be looked for in the south-eastern part of the Asiatic continent, or possibly in the more extensive continent which existed at the time when further India was directly connected with the Sunda Archipelago and eastern Lemuria."
HAECKEL (1876): "The history of Creation."
Fig.2. and 3. Ernst Haeckel, "A hypothetical sketch of the monophyletic origin and extension of the twelve races of Man from Lemuria over Earth", from "Natrliche Schpfungsgeschichte", Plate XV. Note the differences in the German version (1868) without Lemuria and the English version (1876) with Lemuria, after 1870 Haeckel adopted and promoted the idea of a sunken continent in the Indian Ocean (image in public domain).
"The probable primeval home or "Paradise" is here assumed to be Lemuria, a tropical continent at present lying below the level of the Indian Ocean, the former existence of which in the tertiary period seems very probable from numerous facts in animal and vegetable geography. But it is also very possible that the hypothetical "cradle of the human race" lay further to the east (in Hindostan or Further India), or further to the west (in eastern Africa)."
HAECKEL in 1870.
Haeckels work, as vague at is was, however spread the idea of sunken continents to a larger public, still in 1919 the British author Herbert George Wells wrote:
"We do not know yet the region in which the ancestors of the brownish Neolithic peoples worked their way up from the Palaeolithic stage of human development. Probably it was somewhere about south-western Asia, or in some region now submerged beneath the Mediterranean Sea or the Indian Ocean, that, while the Neanderthal men still lived their hard lives in the bleak climate of a glaciated Europe, the ancestors, of the white men developed the rude arts of their Later Palaeolithic period."
WELLS (1919): "Outline of History."
The idea of Lemuria, as lost cradle of humankind, was too intriguing for pseudoscientific and esoteric groups and authors not to be incorporated in their worldview.
In 1888 the Russian medium Elena Petrovna Blavatskaja (1831-1891), strongly influenced by Asian philosophy, published her book on "The secret doctrine", in which she proposes Lemuria as the cradle of one of the seven races of humanity. These beings supposedly possessed four arms and eyes and were egg-laying hermaphrodites, sharing Lemuria with dinosaurs. The mythical Lemuria became part of popular culture
RAMASWAMY, S. (2004): The lost land of Lemuria - Fabulous geographies, catastrophic histories. University of California Press: 334