I had this happen to me once, except it was a much smaller island that only had enough room for 2 settlements, and there were no other opponents on the Island. Thankfully there was about 3 champions on the island, 2 of which had the merchant + earth spellbook abilities, so it wasn't a real problem that game (quite the contrary in fact!). This was back in 0.983 mind, I had saved the game before landraising my way to the mainland, but the save files have since been... gone.

The fact that you got continents is an extremely rare occurrence (but it does happen). I can tell you from approximately a thousand maps I have generated and used maphack to see the entire map (as part of modding stamps), I have never once seen a map divided into continents. 

That is not to say it doesn't happen. CLEARLY it happens. But being so rare is why it is hard to replicate, which is why they'd want your saves.