(d)(e)(f)Fig. 4.2.Geomorphological changes in the Thermaic Gulf from the late classical
period to the early twentieth centuryad. 4.2d shows the narrowing of the plain,
although river craft could still gain access to Pella via a narrow channel,c. 400 bc.By
the time that Macedonia became a Roman province, the harbour of Pella was silting
up (4.2e); byad400, Pella was 28 km from the coast, while the Roman bridge at
Klidi reinforces the eastward trend of communications in imperial times (4.2f ).