Streamlined Islands in Hrad Vallis (possible natural colors; credits: Lunexit)

This image shows a portion of Hrad Vallis, an approx. 400 mt (1300 feet) deep and about 800 Km (approx. 500 mile) long depression located in the Elysium Planitia.

Hrad Vallis is one of several channel systems that are found just West of the Elysium volcanoes. The scoured floor of Hrad Vallis shows the effects of erosion, presumably by water.
Flowing water in the past has carved and sculpted rocky masses into streamlined shapes or islands. The streamlined islands often have sharp edges and are narrower at the downstream end and wider at the upstream end. The streamlined islands visible here are located in an area where the flow condensed from the fractured terrain of the Hrad Valles headwaters (to the South-East) to a more regular channel (to the North-West).