Ignatius Donnelly explains how we know the Irish came form Atlantis:
The Book of Genesis (chap. x.) gives us the descendants of Noah's three sons...The Irish annals take up the genealogy of Magog's family where the Bible leaves it. The Book of Invasions, the "Cin of Drom-Snechta," claims that these Scythians were the Phœnicians; and we are told that a branch of this family were driven out of Egypt in the time of Moses: "He wandered through Africa for forty-two years, and passed by the lake of Salivæ to the altars of the Philistines, and between Rusicada and the mountains Azure, and he came by the river Monlon, and by the sea to the Pillars of Hercules, and through the Tuscan sea, and he made for Spain, and dwelt there many years, and he increased and multiplied, and his people were multiplied."I didn't realize they spoke Gaelic in Atlantis, but who can argue with that proof? I suspect, however, the reason the above has puzzled the Aryan scholars has less to do with the Irish not sharing the double-secret location of Atlantis than with modern misidentification of the locations the Irish did leave us.
From all these facts it appears that the population of Ireland came from the West, and not from Asia--that it was one of the many waves of population flowing out from the Island of Atlantis - and herein we find the explanation of that problem which has puzzled the Aryan scholars...
The itinerary above, from Egypt to Spain (and thence to Ireland) appears not in the Cin of Drom Snechta (which has been lost by all accounts), but in Nennius Chapter 15 and in modified form* in Geoffrey of Monmouth, Chapter 11. Looking at each of the locations in isolation will allow us to draw a pretty good map. Somehow Atlantis doesn't make the list:
The company leaves Egypt and reaches the lake of Salinae (latin: lacum salinarum, or lake of salt mines). These are the north African salt lagoons that still exist today - they run much of the length of the south Mediterranean shoreline - and would have been important to sailors who wanted to salt fish for the trip. So we are heading west along the north coast of Africa towards Cyrene.
Next up we reach the Altars of the Philistines (latin: Ares Filistinorum), which do not exist. Instead the correct identification is the Altars of the Philaeni, which were two sand dunes that marked the border of Cyrene and Carthage in the 2nd century bc (Sallust, in his Jugurthine Wars, explains their location and the mythology behind them). How do they become Altars of the Philistines? In late Roman times both Cyrene and Carthage were taken into the Roman empire and the border ceased to exist, therefore the name of the border marker was lost. Medieval British monks who copied the scrolls did not recognize either the word Philaeni (which had been transposed into Latin from Greek) or the geography, so they replaced it with a word that was familiar, Filistinorum, Philistines). But one looking for Philaeni is going west along the north coast of Africa, one looking for Philistines is going north toward Syria**.
Next up we go between Rusicada and the Mountains Azure (Latin: montes Azariea). Rusicada is the port attached to the old Numidian capital, Cirta (many major cities were not on the seashore, but - like Rome itself - had service ports a few miles away. This kept the damage wrought by pirates to a minimum.) Now, what mountains would be on the other side of Rusicada? The mountains of Sardinia, 120 miles away. In Sardinia was a tribe called the Aisaronesioi, whence the name of the mountains apparently derives. By sighting the mountains on the north (right-hand) one could continue west while staying well off the Numidian coast. Why would one want to do that? To avoid pirates.
Next we come by the river Monlon (Latin: malvam). Why this river of the dozens that flow into the Med? Then known as the Malva and called today the Moulouya, its only importance lies in the fact that it served as the border of Numidia on the east and Mauritania on the west. In fact, Nennius notes (though it's not in the quote above) that the crew then entered Mauritania (modern Morocco). We are still traveling west on the Med***.
Next we reach the Pillars of Hercules, leftovers from his seventh task (delivering sheep or somesuch). He bored straight through a mountain and inadvertently connected the Med with the Atlantic, and mountains north and south of the Strait of Gibraltar are still called his pillars. So we have reached the western end of the Med.
Then we skip through the Tuscan (Latin: Tyrrhenum) Sea to Spain. The Tyrrhennian Sea today is technically the area of the Med between Italy, Sicily, and Sardinia but in ancient days was applied to the entire Mediterranean. So we've just skipped over the Strait from Morocco to Spain.
The Irish did not come from the west at all, but to the West right across the north coast of Africa to Spain and from there**** to Ireland. Where then does that leave Atlantis? I guess Aryan scholars are just going to have to keep looking. The Irish don't appear to know; they were never there.
* Geoffrey applies it to the British, not the Irish.
**Which is why some English versions of Nennius call montes Azariea the "mounds of Syria;" they are traveling the wrong way.
*** And we're doing it before the middle of the First Century when Claudius renamed Numidia to Mauritinia Ceasariensis, giving us two Mauritanias. The Malva remained the border between them.
**** And as the Scotsman recently reports that DNA shows a significant genetic connection between the Spanish and the Irish, it appears science is finally catching up to history, at least in this case.