After the river men had traded with the Indians the steamer proceeded upstream, while Schwatka and his party started downstream again on the raft. In a little while the country began to grow hilly once more, greatly to the delight of the travelers, for the low region had been unendurably dreary. The hilly region is known as the Lower Ramparts, and its scenery is much like that of the Upper Ramparts. Another trading station was soon reached, where Schwatka saw the northernmost garden in the United States. This garden, within two days’ journey of the polar regions, belonged to the white man who was in charge of the station at that point. In it were growing turnips and other hardy vegetables, which tasted delicious to the men, who had been living so long upon canned foods. The raft was laid away at this place, after its journey of thirteen hundred and three miles, and the party embarked on a schooner, hoping to make better time. But they were forced to work their way down the river inch by inch, for heavy winds sprang up and more than once threatened to wreck the schooner. The _Yukon_ at last overtook them, on her return to the mouth of the river, as Schwatka had expected. [Illustration: THE RAFT ON WHICH A JOURNEY OF THIRTEEN HUNDRED AND THREE MILES WAS MADE.] The great delta of the Yukon soon came into view. It consists of many islands and channels which have never been entirely explored. From the most northern mouth of the delta to the most southern is a distance of ninety miles. After the Alphoon, the northernmost mouth, was reached, a weary time began. The vessel slowly threaded her way through shallow channels of water and between mud banks, until she crept into the harbor of the little village of St. Michael on the coast. From this place Schwatka and his party embarked for San Francisco on the _Leo_, which had stopped at St. Michael on its way from Point Barrow. By this raft journey of Lieutenant Schwatka, the Yukon was navigated from its source to its mouth, a distance of two thousand and forty-four miles. This river is the fifth in length in the United States, and sends forth such a volume of water that it freshens Bering sea to a distance of ten miles. XVI. NANSEN CROSSES GREENLAND 1888 Schwatka had explored the interior of Alaska, but the interior of Greenland remained as great a mystery as ever. The only man who had attempted to cross the inland region was Nordenskjöld, who had penetrated only a few miles. In 1888 a young Norwegian named Fridtjof Nansen determined to cross the ice cap of Greenland.