Tarsa

The Tarsa is, despite its relative shortness (approximately 274 kilometres or 170 miles), one of the more important rivers of western Messenia. It has historically been one of the main arteries of commerce in Siurskeyti and Helminthasse until well into modern times. The capitals of both countries – Ostari and Virkið respectively – stand on its banks, and are separated by less than 150 kilometres.

The etymology of the name is uncertain; however, most available evidence suggests a derivation from the Antissan dassu, “strong, heavy”, and Járn Gröfi’s 1992 study accepts this interpretation. The river is fast-flowing for large stretches of its length, and parts of the river above Ostari can see significant tidal bores during exceptionally high tides.

The Tarsa rises in the east of the commonhold of Helminthasse, to the south-east of the town of Garstaður; it flows broadly north-westward for some distance before turning south-west just before Styrskot and continuing in that general direction towards the sea. Broadening in its central reaches, it divides around the riparine island of Þeinsey, on which central Virkið stands, before crossing the border into Siurskeyti just south of Fensbrú. It then continues for a short stretch across Móðalund and into Vonskil. Ostari lies mainly on its southern bank, a short distance before it empties into the Ostarskurflói, an inlet of the Medius Sea, at Törsuós.

The Tarsa valley was the location of the first rail links between Siurskeyti and Helminthasse, completed in 1879 by a consortium led by the Helmin entrepreneur Haraldur Hvildarbarn; although at first the different rail gauges used in each country obliged a break of journey and transhipment of goods – this taking place at Fensbrú, the first town of significant size on the Helmin side of the border – the line was later replaced by a direct link constructed to the standard gauge used in Siurskeyti. The Arpésabrú, on the border between Móðalund and Vonskil, is the largest bridge on the line, and remains today as one of the most impressive feats of railway engineering in Siurskeyti.

The river also lends its name to the prehistoric family of sea reptiles, the Tarsasauridae; specimens of the earliest exemplar, Tarsasaurus, were excavated at Pýrshöll, roughly 25 kilometres upriver from Ostari, in 1887.