Yes, they are.
A pre-Adamic race existed. This is what Cayce called the third root race, this is indeed when souls separated into male and female, the yin and yang of one consciousness, and Amilius and Lilith were the first to take on this more physical body. The readings give 106.000 B.C. for Amilius and Lilith, Atlantis was the first Eden. Souls at the time were using other creatures and lifeforms in ways to experiment with this dimension, so many were connected, or better said possessed animal bodies, that became a part of their consciousness.
According to Cayce readings, Amilius and Lilith were the first incarnation of the Logos, or Christ. Many other souls followed their example in creating the dual qualities in two separate bodies. The purpose was to create the perfect companionship , since the separation from their spiritual oneness, where all is experienced as one whole, this new world was a lonely place to be in.
So Amilius continued to create better physical conditions, for other souls to live in, this all in accordance with the Creative Forces. His followers were the Children of the Law of one.
But there were souls who sought more and more self, these so called Sons of Belial, used these same forces for selfish purposes, resulting in moral decadence, greed and competition. So Esai, one of the Belial group replaced Amilius and this eventually lead to the catastrophic events that sank the continent that was Atlantis. Those of the Law of One fled the country and migrated to America, the Pyrenees, Egypt, and other places to continue their work. Since the fall of souls into this dimension, the way out is through matter, so better and more perfect bodies were created for this purpose.
In fact some reincarnation theories give the same evolution.
Btw, According to Cayce, human souls began entering 10.5 million years ago, Atlantis dates from 210.000 years ago, during which a third wave of souls entered.
Edgar Cayce's Atlantis, Drs. Gregory and Lora Little & John van Auken.
More on Atlantis according to Cayce readings here; [www.dreamscape.com]