I found some background info on Wikipedia that may help.
"In 1864 the zoologist and biogeographer Philip Sclater wrote an article on "The Mammals of Madagascar" in The Quarterly Journal of Science. Using a classification he referred to as lemurs but which included related primate groups, and puzzled by the presence of their fossils in both Madagascar and India but not in Africa or the Middle East, Sclater proposed that Madagascar and India had once been part of a larger continent."
"The anomalies of the Mammal fauna of Madagascar can best be explained by supposing that ... a large continent occupied parts of the Atlantic and Indian Oceans ... that this continent was broken up into islands, of which some have become amalgamated with ... Africa, some ... with what is now Asia; and that in Madagascar and the Mascarene Islands we have existing relics of this great continent, for which ... I should propose the name Lemuria!"-Philip Sclater
" Lemuria entered the lexicon of the occult through the works of Helena Blavatsky, who claimed that the Mahatmas had shown her an ancient, pre-Atlantean Book of Dzyan. Lemuria is mentioned in one of the 1882 Mahatma Letters to A. P. Sinnett. According to L. Sprague de Camp, Blavatsky's concept of Lemuria was influenced by other contemporaneous writers on the theme of lost continents, notably Ignatius L. Donnelly, American cult leader Thomas Lake Harris and the French writer Louis Jacolliot.
Within Blavatsky's complex cosmology, which includes seven "Root Races", the "Third Root Race" occupied Lemuria. She describes them as about 7 feet (2.1 m) tall, sexually hermaphroditic, egg-laying, mentally undeveloped and spiritually more pure than the following "Root Races". Before the coming of the Lemurians, the second "Root Race" is said to have dwelled in Hyperborea. After the subsequent creation of mammals, Mme Blavatsky revealed to her readers, some Lemurians turned to bestiality. The gods, aghast at the behavior of these "mindless" men, sank Lemuria into the ocean and created a "Fourth Root Race" endowed with intellect on Atlantis.
The later theosophical author William Scott-Elliot gave one of the most elaborate accounts of lost continents. The English theosophist received his knowledge from Charles Webster Leadbeater, who communicated with the Theosophical Masters by "astral clairvoyance". In 1896 he published The Story of Atlantis, followed in 1904 by The Lost Lemuria, in which he included a map of the continent of Lemuria as stretching from the east coast of Africa across the Indian and the Pacific Oceans.
James Bramwell portrayed Lemuria in his book, Lost Atlantis, as "a continent that occupied a large part of what is now the South Pacific Ocean". He described the people of Lemuria in detail and characterised them as one of the "root-races of humanity". According to Bramwell, Lemurians are the ancestors of the Atlanteans, who survived the period "of the general racial decadence which affected the Lemurians in the last stages of their evolution". From "a select division of" the Atlanteans after their promotion to decadence Bramwell claims the Aryan race arose. "Lemurians, Atlanteans, and Aryans are root-races of humanity", according to Bramwell."
"In 1894, Frederick Spencer Oliver published A Dweller on Two Planets, which claimed that survivors from a sunken continent called Lemuria were living in or on Mount Shasta in northern California. Oliver claimed the Lemurians lived in a complex of tunnels beneath the mountain and occasionally were seen walking the surface dressed in white robes.
In 1931 Harvey Spencer Lewis using the pseudonym Wisar Spenle Cerve wrote a book (published by the Rosicrucians) about the hidden Lemurians of Mount Shasta that a bibliography on Mount Shasta described as "responsible for the legend's widespread popularity." This belief has since been repeated by Guy Warren Ballard, followers of the Ascended Masters and the Great White Brotherhood, and Bridge to Freedom, The Summit Lighthouse, Church Universal and Triumphant, and Kryon.
Some Tamil writers such as Devaneya Pavanar have tried to associate Lemuria with Kumari Kandam, a legendary sunken landmass mentioned in the Tamil literature, claiming that it was the cradle of civilization."