We shall easily recollect the great water-system of North America if we consider it to be represented by an irregular cross, of which the Mississippi with its affluents forms the stem; Lake Superior and the River Saint Lawrence, including the intermediate lakes, the eastern arm; the Lake of the Woods and its neighbours, Lake Winnipeg and the Saskatchewan, the western arm; and the northern lakes of Athabasca, the Great Slave Lake, and the Mackenzie River, the upper part of the cross. If we observe also a wide level region which runs north and south between the Arctic Ocean and the Gulf of Mexico, bounded on either side by the two lofty mountain ranges already mentioned, we shall have a tolerably correct notion of the chief physical features of the North American continent. Arriving at the northern end, we shall find it reaching some four degrees north of the Polar Circle, though some of its headlands extend stilt further into the icy sea. Beyond it stretches away to an unknown distance towards the Pole a dense archipelago of large islands, the narrow channels between them bridged over in winter by massive sheets of ice, affording an easy passage to the reindeer, musk-oxen, and other animals which migrate southward during the colder portion of the Arctic winter. NORTHERN REGION. With that end of America will ever be associated the names of Sir John Franklin and his gallant companions, who perished in their search of the North-west Passage; as well as those of other more fortunate successors, especially of Captains McClure and Collinson of the British navy, to the first of whom is due the honour of leading an expedition from west to east along that icy shore; while Captain Collinson took his ship, the _Enterprise_, up to Cambridge Bay, Victoria Land, further east than any ship had before reached from the west--namely, 105 degrees west--and succeeded in extricating her from amid the ice and bringing her home in safety. Captain McClure, not so fortunate in one respect, was compelled to leave his ship frozen up. The two expeditions, while proving the existence of a channel, at the same time showed its uselessness as a means of passing from the Atlantic to the Pacific, as, except in most extraordinary seasons, it remains blocked up all the year by ice.