The best information I have found comes from the Ra material
You may find more information from the work of Paul Shockley or Edgar Cayce, as Ra informs us that entity spent time with Atlantis.
Also prior to discovering the Ra material, I studied the Emerald Tablets of Thoth, he was an Atlantean, and there are insights to be found there as well.
Quote:The Atlantean race was a very conglomerate social complex which began to form approximately 31,000 years in the past of your space/time continuum illusion. It was a slow growing and very agrarian one until approximately 15,000 of your years ago. It reached quickly a high technological understanding which caused it to be able to use intelligent infinity in an informative manner. We may add that they used intelligent energy as well, manipulating greatly the natural influxes of the indigo or pineal ray from divine or infinite energy. Thus, they were able to create life forms. This they began to do instead of healing and perfecting their own mind/body/spirit complexes, turning their distortions towards what you may call negative.
Approximately 11,000 of your years ago, the first of the, what you call, wars, caused approximately forty percent of this population to leave the density by means of disintegration of the body. The second and most devastating of the conflicts occurred approximately 10,821 years in the past according to your illusion. This created an earth-changing configuration and the large part of Atlantis was no more, having been inundated. Three of the positively-oriented of the Atlantean groups left this geographical locus before that devastation, placing themselves in the mountain areas of what you call Tibet, what you call Peru, and what you call Turkey.
Do you have any brief questions before we close this meeting?
14.4 Questioner: I understand from previous material that this occurred 75,000 years ago. It was then that our third-density process of evolution began. Can you tell me the history, hitting only the points of development, shall I say, that occurred within this 75,000 years, any point when contact was made to aid this development?
Ra: I am Ra. The first attempt to aid your peoples was at the time 75,000. This attempt 75,000 of your years ago has been previously described by us. The next attempt was approximately 58,000 of your years ago, continuing for a long period in your measurement, with those of Mu as you call this race or mind/body/spirit social complex. The next attempt was long in coming and occurred approximately 13,000 of your years ago when some intelligent information was offered to those of Atlantis, this being of the same type of healing and crystal working of which we have spoken previously. The next attempt was 11,000 of your years ago. These are approximations as we are not totally able to process your space/time continuum measurement system. This was in what you call Egypt and of this we have also spoken. The same beings who came with us returned approximately 3,500 years later in order to attempt to aid the South American mind/body/spirit social complex once again. However, the pyramids of those so-called cities were not to be used in the appropriate fashion.
Therefore, this was not pursued further. There was a landing approximately 3,000 of your years ago also in your South America, as you call it. There were a few attempts to aid your peoples approximately 2,300 years ago, this in the area of Egypt. The remaining part of the cycle, we have never been gone from your fifth dimension and have been working in this last minor cycle to prepare for harvest.
21.19 Questioner: Thank you very much. I apologize in being so stupid in stating my questions but this has cleared up my understanding nicely.
Then in the second 25,000 year major cycle was there any great civilization that developed?
Ra: I am Ra. In the sense of greatness of technology there were no great societies during this cycle. There was some advancement among those of Deneb who had chosen to incarnate as a body in what you would call China.
There were appropriately positive steps in activating the green-ray energy complex in many portions of your planetary sphere including the Americas, the continent which you call Africa, the island which you call Australia, and that which you know as India, as well as various scattered peoples.
None of these became what you would name great as the greatness of Lemuria or Atlantis is known to you due to the formation of strong social complexes and in the case of Atlantis, very great technological understandings.
However, in the South American area of your planetary sphere as you know it, there grew to be a great vibratory distortion towards love. These entities were harvestable at the end of the second major cycle without ever having formed strong social or technological complexes.
22.20 Questioner: Was this first calling then at a time before Atlantis became technologically advanced?
Ra: I am Ra. This is basically correct.
22.21 Questioner: Then did the technological advancement of Atlantis come because of this call? I am assuming that the call was answered to bring them the Law of One and the Law of Love as a distortion of the Law of One, but did they also then get technological information that caused them to grow into such a highly advanced technological society?
Ra: I am Ra. Not at first. At about the same time as we first appeared in the skies over Egypt and continuing thereafter, other entities of the Confederation appeared unto Atlanteans who had reached a level of philosophical understanding, shall we misuse this word, which was consonant with communication, to encourage and inspire studies in the mystery of unity.
However, requests being made for healing and other understanding, information was passed having to do with crystals and the building of pyramids as well as temples, as you would call them, which were associated with training.
22.27 Questioner: I see. Then I will state the picture I have of Atlantis and you tell me if I am correct.
We have a condition where a large enough percentage of the people of Atlantis had started at least going in the direction of the Law of One and living the Law of One for their call to be heard by the Confederation. This call was heard because, using the Law of Squares, it overrode the opposition of the Atlantean entities who were not calling. The Confederation then used channels such as we use now in communication and also made contact directly, but this turned out to be a mistake because it was perverted by the entities of Atlantis. Is this correct?
Ra: I am Ra. This is correct with one exception. There is only one law. That is the Law of One. Other so-called laws are distortions of this law, some of them primal and most important for progress to be understood. However, it is well that each so-called law, which we also call “way,” be understood as a distortion rather than a law. There is no multiplicity to the Law of One.
This will be the final question in length of this working. Please ask it now.
23.1 Questioner: You were speaking yesterday of the first contact made by the Confederation which occurred during our third major cycle. You stated that you appeared in the skies over Egypt at approximately the same time that aid was given to Atlantis. Can you tell me why you went to Egypt and your orientation of attitude and thinking when you first went to Egypt?
Ra: I am Ra. At the time of which you speak there were those who chose to worship the hawk-headed sun god which you know as vibrational sound complex, “Horus.” This vibrational sound complex has taken other vibrational sound complexes, the object of worship being the sun disc represented in some distortion.
We were drawn to spend some time, as you would call it, scanning the peoples for a serious interest amounting to a seeking with which we might help without infringement. We found that at that time the social complex was quite self-contradictory in its so-called religious beliefs and, therefore, there was not an appropriate calling for our vibration. Thus, at that time, which you know of as approximately 18,000 of your years in the past, we departed without taking action.
Quote:24.2 Questioner: In the last session you mentioned that in this last 25,000 year cycle the Atlanteans, Egyptians, and those in South America were contacted and then the Confederation departed. I understand that the Confederation did not come back for some time. Could you tell me of the reasons, consequences, and attitudes with respect to the next contact with those here on planet Earth?
Ra: I am Ra. In the case of the Atlanteans, enlargements upon the information given resulted in those activities distorted towards bellicosity which resulted in the final second Atlantean catastrophe 10,821 of your years in the past, as you measure time.
Many, many were displaced due to societal actions both upon Atlantis and upon those areas of what you would call North African deserts to which some Atlanteans had gone after the first conflict. Earth changes continued due to these, what you would call, nuclear bombs and other crystal weapons, sinking the last great land masses approximately 9,600 of your years ago.
In the Egyptian and the South American experiments results, though not as widely devastating, were as far from the original intention of the Confederation. It was clear to not only us but also to the Council and the Guardians that our methods were not appropriate for this particular sphere.
Our attitude thus was one of caution, observation, and continuing attempts to creatively discover methods whereby contact from our entities could be of service with the least distortion and above all with the least possibility of becoming perversions or antitheses of our intention in sharing information.
27.1 Questioner: Jim has felt the obligation to ask two questions that were asked of him by Paul Shockley, and I will ask those two first, in case you are able to answer them before we get started. The first question: Paul Shockley is presently channeling the same source which Edgar Cayce channeled, and he has received information that he took part in the design and construction of the Egyptian pyramids. Can you tell us what his role was in that effort?
Ra: I am Ra. This was in your space/time continuum two periods and two lifetimes. The first of a physical nature working with Confederation entities in what you know of as Atlantis, this approximately 13,000 of your years ago. This memory, shall we say, being integrated into the unconscious of the mind/body/spirit complex of this entity due to its extreme desire to remember the service of healing and polarization possible by the mechanisms of the crystal and the charged healer.
The second experience being approximately 1,000 of your years later during which experience this entity prepared, in some part, the consciousness of the people of what you now call Egypt, that they were able to offer the calling that enabled those of our social memory complex to walk among your peoples. During this life experience this entity was of a priest and teaching nature and succeeded in remembering in semi-distorted form the learn/teachings of the Atlantean pyramidal experiences. Thus this entity became a builder of the archetypal thought of the Law of One with distortions towards healing which aided our people in bringing this through into a physical manifestation.
You may find more information from the work of Paul Shockley or Edgar Cayce, as Ra informs us that entity spent time with Atlantis.
Also prior to discovering the Ra material, I studied the Emerald Tablets of Thoth, he was an Atlantean, and there are insights to be found there as well.