A Shoal of Mud is described by Plato (Timaeus 25d) as marking the location of submerged Atlantis. Assuming that this detail is not an embellishment by Plato, there are a couple of interesting points to be made in respect of this passage. Firstly, there is the fact that Plato uses the present tense implying that this ‘impassable’ shoal was still a maritime hazard in the time of either Solon and/or Plato. Three of the most popular translations clearly indicate this:

Jowett

….the sea in those parts is impassable and impenetrable, because there is a shoal of mud in the way; and this was caused by the subsidence of the island.

Bury

…..the ocean at that spot has now become impassable and unsearchable, being blocked up by the shoal of mud which the island created as it settled down.”

Lee

…..the sea in that area is to this day impassible to navigation, which is hindered by mud just below the surface, the remains of the sunken island.

Secondly, the comment clearly rules out the possibility of a 9600 BC date for the demise of Atlantis, as sea levels have risen hundreds of feet since that time and could never have continued to exist as a navigational barrier during the 1st millennium BC. The triremes of Plato’s time had an estimated draught of about a metre so that the shallows must have had a depth that was less than that. It could be inferred from Plato’s text that barrier presented by the shoals was a continuous feature that did not vary with tidal changes, an idea that is fully compatible with a Mediterranean location for Atlantis. Parts of the Mediterranean experience virtually no tidal changes, as can be seen from the chart. The darkest shade of blue indicates the areas of minimal tidal effect.

If Plato was correct in stating that Atlantis was submerged in a single day and that it was still close to the water’s surface in his own day, its destruction must have taken place a relatively short time before since the slowly rising sea levels would eventually have deepened the waters covering the remains of Atlantis to the point where they would not pose any danger to shipping.

The reference to mud shoal resulting from an earthquake brings to mind the possibility of liquefaction. This perhaps what happened to the two submerged ancient cities close to modern Alexandria. Their remains lie nine metres under the surface of the Mediterranean.

Our knowledge of sea level changes over the past two and a half millennia should enable us to roughly estimate all possible locations in the Mediterranean where the depth of water of any submerged remains would have been a metre or less in the time of Plato.