I am on Solomons Shelf Island and it says expansion unreachable, how can I open more space?

There is no island called Solomon Shelf. On the map, the two islands on either side of Solomon Shelf are Laurel Island and Willow Island, which are islands #3 and #4. There are currently 8 islands for those advanced in the game. To expand further, you need to continue collecting compasses and advancing in the game to fill stars. When you tap on the next available plot, the game will show you how many compasses and how many stars you need to open that plot. There is no where else in the game that shows a compass count.