By the beginning of the 18th century the Dutch settlers had begun to cross the mountains which lie behind the narrow belt of coast land that forms a projection into the ocean on either side of the Cape of Good Hope. Seventy years later the boundaries of Cape Colony on the north and west were the Berg River and the Zwartebergen Mountains, and on the east the Gamtoos River. A few years later the pioneers of colonization had crossed the Berg River, and had established themselves as far north as the Olifants River, so named because earlier explorers had seen on its banks herds of hundreds of elephants. The Orange River was first discovered in 1760; and in 1779 Captain Gordon, a Scotchman in the service of the Dutch Company, had traced it for some distance down to its mouth, and had named it after the head of the Dutch State. Hitherto, the Dutch Government was confined to a narrow coast strip; but in 1785 the district of Graaf Reinet[91] was formed, and the same name was given to the village which formed its capital. Then the Dutch boundary crept up to the Great Fish River, which rises far away to the north, near the course of the Orange River. This Great Fish River remained the easternmost boundary of the Colony in Dutch times. To the north its limits were vague, and in one direction reached nearly to the Orange River, beyond the second great range of South African mountains—the Sneeubergen. But beyond the immediate limits of Cape Colony the Dutch displayed some interest in the fate of South-East Africa. They opened up a furtive and occasional trade with the Portuguese coast of East Africa, which at first began for slaves (numbers of Makua were brought from Moçambique to Cape Town), was continued for tropical products, and, with many interruptions, resulted in the establishment at the present day of important Dutch commercial firms along the Mozambique coast. In 1720, after the evacuation of Mauritius, an expedition was sent from Cape Colony to Delagoa Bay, which, though claimed by the Portuguese, had been abandoned by them at the beginning of the 18th century, so far as actual occupation was concerned (see p. 110). A fort was built by the Dutch which was named Lydzaamheid; and tentative explorations were made in the direction of the Zambezi, from which gold dust was procured. During ten years of occupation, however, the deaths from fever were so numerous that the settlement was given up in 1730.