The Argo Navigates the Symplegades. Source: 1st-art-gallery.com
From the Symplegades to Colchis
PHINEUS had warned the Argonauts of the terrifying rocks, called the Symplegades… which, perpetually shrouded in sea mist, guarded the entrance to the Bosphorus. When a ship attempted to pass between them, they drove together and crushed her; but, at Phineus’s advice, Euphemus let loose a dove… to fly ahead of the Argo. (From the Symplegades to Colchis, The Greek Myths by Robert Graves, pp 594-598).
As the dove flew through the channel between the rocks, the Symplegades moved together, clipping the bird’s tail. In the brief interval between the rocks returning to their original position and their sensing further movement, the Argo sped through the gap, missing being destroyed by the returning rocks by inches.
The Argonauts then pursued an uneventful course along the Black Sea coast, although tragedy struck when they put in at Marindyne, a city ruled by King Lycus, an enemy of the boxer-king Amycus, whom Polydeuces had killed. The crew were therefore given a warm welcome by the delighted Lycus. However the following day, Idmon, the Argo’s seer was attacked and fatally wounded by a wild boar. Soon after the navigator Tiphys also died, this time of an illness. Although Jason was able to recruit replacements for these losses in Sinope, the Argo's next landfall, the crew was nonetheless weakened. The expedition pressed on until the Caucasus Mountains came into view, indicating that Colchis was close. Jason concealed the vessel in a backwater and then called a council of war.
Graves suggests that the legend of the Clashing Rocks may come from large icebergs that found their way into the Black Sea from Russia when the frozen rivers thawed in the spring. Colchis is estimated to be located in modern Georgia.