Extract Two
The identity of the island of Ictis would appear to be more elusive. Scholarly opinion meanders between St Michael’s Mount and the Isle of Wight with various other less likely stop-offs along the way. But this is because the expertise of the scholars derives wholly from the humanities. If they had any kind of background in the Earth Sciences they would be able to identify Ictis with considerable confidence just from the information Diodorus has supplied:
1. The phrase “buy the tin from the natives and carry it over to Gaul” implies that Ictis is somewhere on the south coast of Britain.
2. The phrase “during the ebb of the tide the intervening space is left dry” implies that Ictis is a tidal island, a piece of land joined to the mainland at low tide but cut off from it at high tide.
3. There are just three 'tidal islands' on the south coast of Britain:
Burry Island in Portsmouth Harbour, Hampshire;
Burgh Island south of Plymouth, Devon
St Michael’s Mount near Land’s End in Cornwall.
4. The phrase “they carry over to the island the tin in abundance in their wagons” implies that there was a causeway between the mainland and the island since wheeled traffic is not generally speaking possible over the treacherous sand and unpredictable rocks of any intertidal foreshore.
5. Burgh Island and St Michael’s Mount both have causeways, Burry Island does not.
6. Burgh Island and St Michael’s Mount are at either end of the tin-producing area of Cornwall and West Devon so both would qualify as ideal tin-exporting centres.
7. The phrase “carry it over to Gaul, and after travelling overland for about thirty days, they finally bring their loads on horses to the mouth of the Rhone” implies that the tin was being taken to Normandy for onward transmission via the shortest overland route through France.
8. Burgh Island is the nearest part of the tin area to Normandy; St Michael's Mount is the furthest.
9. Burgh Island is Ictis.