THE GUIANA UPLANDS. 11 



At their eastern extremity the Tumuc-IIumac mountains ramify like the ribs 

 of a fan towards the north-east, the east and south-east, but retain the aspect of 

 distinct ridges only above the low-lying marshy tracts. About the sources of the 

 Oyapok between these ridges the water-partings are so indistinct that the channels 

 of the Oyapok, Cachipour, Araguari, and even of the Yari affluent of the Amazons, 

 are all connected during the rainy season by continuous chains of meres and 

 lagoons. These shallow expanses, however, are unnavigable and inaccessible even 

 to the canoes of the surrounding Indian tribes. 



In that section of the Guianas which is comprised between the southern 

 uplands and the seacoast, there nowhere occur any heights forming continuous 

 chains of mountains or hills. Here all the rising grounds are broken by tlie 

 fluvial valleys into separate ridges of short length, such as the so-called 

 " Montagne Française " on the right bank of the Maroni ; the Magnetic 

 Mountain (715 feet) towards the south-east between the Inini and Mana rivers; 

 and the granitic Mount Leblond (1,335 feet), towards the sources of the Sinnamari. 



Near the shore the eminences are for the most part merely isolated masses of 

 gneiss, schists, or sandstone ranging in height from 300 to 720 feet. Formerly 

 washed by the marine waves, they are now surrounded by alluvial matter deposited 

 in the marine waters. One line of beach after another was here laid down, 

 enclosing the old islands and arcLipelagoes, which are now to be sought in the 

 interior of the Continent. 



In French Guiana nothing is seen along the seaboard except a few rocky 

 prominences on the beach or in the vicinity of the coast. North-west of Cayenne 

 a few bluffs stand out near Mana, Iracoubo, Sinnamari, and Kourou. South-east 

 of the capital stretch the hills of Caux, whose French name, as spelt in the eigh- 

 teenth century, has been altered to the English form Kaw. This range of coast 

 hills culminates in Mount Matouri (836 feet), in the " Tour de l'Ile," south of 

 Cayenne. Mount Argent, serving as a landmark to mariners at the mouth of the 

 Oyapok, is a mere hillock scarcely 300 feet high. 



The district Imown as the " island of Cayenne," though separated from the 

 mainland only by a few marshy channels, is also studded with knolls representing 

 former islands now connected b}^ sedimentary deposits. Such are Cabassou 

 dominating the capital, and farther east the Remire '' Mountains," which were 

 formerly called volcanoes. The neighbouring depressions where rise the springs 

 which supply Cayenne with water were similarly regarded as old " craters." 



Along the coast occur a few rocky islets, of which the most important, 

 thanks to its deep anchorage, is the Salut Archipelago ; farther east are the Enfant 

 Perdu ; the Malingre, Père, Mère and Mamelles, all disposed in a chain parallel 

 with the shore ; lastly, farther seaward, the two Connétables facing the mouth of 

 the Approuague, upheaved peaks of a submarine plateau. 



Rivers of Guiana — The Essequibo Basin. 

 The Essequibo (Essequebo), largest of all the Guiana rivers, flows entirely in 

 British territory ; but the Cuyuni, one of its chief affluents, takes its rise beyond 



