Grand Erg Oriental follow the wind's direction. There are other types of dunes, as well as "complex" dunes. Saharan winds are also known to clear an area of sand altogether, leaving bare rock (hamada) or gravel (reg). The "Grand Erg Oriental" is accessible overland by an Algerian road, which goes south from Constantine. It passes through the Aurès mountains, then salt lakes by the city of Biskra. Next the road skirts the western edge of the erg. After about 500 km. in all, it reaches the ancient oasis of Ourgla [Wargla]. Since late antiquity Wargla was a stop for the Saharan trade, being
Erg (tug) of Canada, which kept records of the activity in the harbour, advised that from 1940 to 1943, there were at least 12 vessels involved in accidents within Halifax Harbour. Vessels such as "Camperdown", "Claire Lilley" and "Nueva Indalucia" ran aground, whereas others such as "Otter", and "Trongate" caught fire and sank (or, in the case of "Trongate", was made to sink as the flames were completely out of control). In 1940, "Herbidean" was sunk by the British ship "Esmond"; a forerunner to the fate of "Erg". On June 6, 1943, "Erg" was carrying workers and equipment (air compressors and electric