As I have banged on about before, platos works are symbolic fiction. It has been done before and since, Virgils Aeneid and Moore's Utopia. Please
read the story and not peoples opinions on them. Here is a link to the full text of Critias.
why is there no search for utopia? Because it is a work of fiction just like gullivers travels. the detail is there as symbolism and to add
authenticity. It would be a serious underestimation of plato's gifts as a writer to think other wise. Here is a v good critique I found on net.
Qouted from project guttenburg e-text
Plato, as he has already told us (Tim.), intended to represent the ideal state engaged
in a patriotic conflict. This mythical conflict is prophetic or symbolical
of the struggle of Athens and Persia, perhaps in some degree also of the
wars of the Greeks and Carthaginians, in the same way that the Persian is
prefigured by the Trojan war to the mind of Herodotus, or as the narrative
of the first part of the Aeneid is intended by Virgil to foreshadow the
wars of Carthage and Rome. The small number of the primitive Athenian
citizens (20,000), 'which is about their present number' (Crit.), is
evidently designed to contrast with the myriads and barbaric array of the
Atlantic hosts. The passing remark in the Timaeus that Athens was left
alone in the struggle, in which she conquered and became the liberator of
Greece, is also an allusion to the later history. Hence we may safely
conclude that the entire narrative is due to the imagination of Plato, who
has used the name of Solon and introduced the Egyptian priests to give
verisimilitude to his story. To the Greek such a tale, like that of the
earth-born men, would have seemed perfectly accordant with the character of
his mythology, and not more marvellous than the wonders of the East
narrated by Herodotus and others: he might have been deceived into
believing it. But it appears strange that later ages should have been
imposed upon by the fiction. As many attempts have been made to find the
great island of Atlantis, as to discover the country of the lost tribes.
Without regard to the description of Plato, and without a suspicion that
the whole narrative is a fabrication, interpreters have looked for the spot
in every part of the globe, America, Arabia Felix, Ceylon, Palestine,
Sardinia, Sweden.
Timaeus concludes with a prayer that his words may be acceptable to the God
whom he has revealed, and Critias, whose turn follows, begs that a larger
measure of indulgence may be conceded to him, because he has to speak of
men whom we know and not of gods whom we do not know. Socrates readily
grants his request, and anticipating that Hermocrates will make a similar
petition, extends by anticipation a like indulgence to him.
Critias returns to his story, professing only to repeat what Solon was told
by the priests. The war of which he was about to speak had occurred 9000
years ago. One of the combatants was the city of Athens, the other was the
great island of Atlantis. Critias proposes to speak of these rival powers
first of all, giving to Athens the precedence; the various tribes of Greeks
and barbarians who took part in the war will be dealt with as they
successively appear on the scene.
Its very long but relevant to the disscussion. I want to believe there was an ancient civ before our own technologiccally advanced, indeed there is a
lot of evidence to support it, but platos work does not point to this as an accurate description. I accept the source of the text could come from some
form of greek mythology, but not physical evidence.
Well thats my ten cents. Thanks for listening, well reading.
I'll be sure to point people to this to show them the basics about
Atlantis, ive been researching into Atlantis which gives this link added validity 
"A man wiser than me" so it must be true. (Get it?) 
