Tho Clark Ashton Smith wrote of Hyperborea and Atlantis (3 tales), the French states of Averoigne and Malneant, and the far future continent of Zothique, he wrote very little on Lemuria. One poem describes a cruel evil god named Tolometh.
You probably already know this, but the theory of Lemuria was created specifically because scientists couldn't explain how related primate species (lemurs) could be found in both Madagascar and India, but not in Africa or the Arabian Peninsula. This was before the theory of tectonic plates was universally accepted and the idea of "land bridges" was used by most scientists to explain how related animal species could be found in different parts of the world. Lemuria was never a part of mythology or the stories of ancient cultures. It was simply created by a scientist whose work has largely been disproven by modern science. "Kumari Kandam" on the other hand is akin to Atlantis in the Indian Ocean according to ancient Indian writings.