Why are two cities disconnected?

[Davy]

Hi, two cities on the map are disconnected, why? Thanks!

 

[Verrucosus]

It seems like the two tree tiles to the west of Babylon's garrison tile are connected to Babylon by river. However, the river does not touch the third tile to the west of the garrison, so the second tile (at the centre of the screenshot) needs a road to complete the connection.

 

[Davy]

It seems like the two tree tiles to the west of Babylon's garrison tile are connected to Babylon by river. However, the river does not touch the third tile to the west of the garrison, so the second tile (at the centre of the screenshot) needs a road to complete the connection.

Thanks!