St. Lawrence, whose shape points to the old fluvial nuclei of settlement.  Similarly the early Dutch grants on the Hudson gave to the patroons four miles along the river and an indefinite extension back from the stream.  In the early Connecticut River settlements, the same consideration of a share in the river and its alluvial bottoms distributed the town lots among the inhabitants in long narrow strips running back from the banks.[710]

[Sidenote:  Boatmen tribes or castes.]

In undeveloped countries, where rivers are the chief highways, we occasionally see the survival of a distinct race of boatmen amid an intruding people of different stock, preserved in their purity by their peculiar occupation, which has given them the aloofness of a caste.  In the Kwang-tung province of southern China are 40,000 Tanka boat people, who live in boats and pile-dwellings in the Canton River.  The Chinese, from whom they are quite distinct, regard them as a remnant of the original population, which was dislodged by their invasion and forced to take refuge on the water.  They gradually established intercourse with the conquerors of the land, but held themselves aloof.  They marry only among themselves, have their own customs, and enjoy a practical monopoly of carrying passengers and messages between the steamers and the shore at Macao, Hongkong and Canton.[711] In the same way, the middle Niger above Gao possesses a distinct aquatic people, the Somnos or Bosos, who earn their living as fishermen and boatmen on the river.  They spread their villages along the Niger and its tributaries, and occupy separate quarters in the large towns like Gao and Timbuctoo.  They are creatures of the river rather than of the land, and show great skill and endurance in paddling and poling their narrow dugouts on their long Niger voyages.[712]

Reference has been made before to the large river population of China who live on boats and rafts, and forward the trade of the vast inland waterways.  These are people, differentiated not in race, but in occupation and mode of life, constantly recruited from the congested population of the land.  Allied to them are the trackers or towing crews whose villages form a distinctive feature of the turbulent upper Yangtze, and who are employed, sometimes three hundred at a time, to drag junks up the succession of rapids above Ichang.[713] Similarly the complex of navigable waterways centering about Paris, as far back as the reign of Tiberius Caesar, gave rise to the Nautae Parisii or guild of mariners, from whom the city of Paris derived its present coat of arms—­a vessel under full sail.  These Lutetian boatmen handled the river traffic in all the territory drained by the Seine, Marne, and Oise.  Later, in the reign of Louis the Fat, they were succeeded by the Mercatores aquae Parisiaci, and from them sprang the municipal body appointed to regulate the river navigation and commerce.[714]

[Sidenote:  River islands as protected sites.]