Archaeologists seeking traces of what could be Europe's oldest settlement in waters off southern Greece say they have located promising indications of human activity and sections of a deep-sunken prehistoric coastline.

Greece's Culture Ministry said Friday the Swiss-Greek mission plans an undersea excavation in coming years in areas pinpointed during an initial survey last month.

Archaeologists hope the investigation off the seaside Franchthi Cave, an important prehistoric site, will help show how the first farming communities spread through Europe in Neolithic times about 9,000 years ago.

While very early stone tools, pottery and ornaments were found in the cave, where they were made, remains a mystery and the Swiss-Greek team believes the site lies underwater.

Last month's survey also uncovered traces of the prehistoric coastline up to 225 meters (246 yards) deep.