Guiana, in its widest meaning, is the name given to that part of South America that lies between 8 degrees 40 minutes north and 3 degrees 30 minutes south latitude and 50 degrees and 68 degrees 30 minutes west longitude. This vast territory, about 690,000 square miles in area, comprises Venezuelan Guiana, British Guiana, Dutch Guiana (Surinam), French Guiana (Cayenne), and Brazilian Guiana. The first of these divisions is now part of Venezuela and the last is included in Brazil. The coast of British Guiana is fringed by low, alluvial flats, the result of deposit by the rivers. Beginning at three feet below high-water mark, these flats extend inland 25 or 30 miles, rising imperceptibly about 15 feet. Beyond is a broad, rolling region of sandy clay formation, 150 feet above sea-level, which runs back to the forest-covered hills. Two ranges of mountains traverse the country from west to east and a third chain forms the southern boundary and the watershed between the Essequibo and the Amazon. The highest mountain peak is Roraima on the western border, 8635 feet. The rivers of British Guiana and their tributaries form a network of waterways throughout the country and they are practically the only transportation routes from the coast into the interior. The most important are the Essequibo, the Demerara, the Berbice and the Corentyn. The Essequibo has its source in the Acari mountains near the equator at 850 feet above the sea, and it flows north about 600 miles, reaching the Atlantic by an estuary 15 miles wide, in which there are a number of large and fertile islands. At one time sugar cane was grown on four of these islands, but today only one, Wakenaam, has a sugar mill. For the ten months beginning with October and ending in July, the temperature on the coast is even, as the northeast trade winds keep it down to 80 degrees Fahrenheit on an average, but the cessation of the trades in August and September makes the heat oppressive. Hurricanes are unknown and but little damage is caused in the coast regions by earthquakes, owing to the character of the soil. In the interior the year is divided into one wet and one dry season, but in the low-lying coast country, where the sugar plantations are, there are two wet and two dry periods. The long wet season begins about the middle of April and lasts until August; the long dry period is from September to the end of November. The rainfall varies greatly according to locality; on the coast the yearly average is 80 inches. In 1914 the population was estimated to be 304,089; of these 120,000 were negroes, 124,000 East Indians, 11,600 Portuguese, 4300 Europeans of other nationalities, 6500 aborigines and over 30,000 of mixed race.