Sumatra, the largest of the islands, is but thinly peopled; the greater part of the surface is covered with dense forest, the cultivated area being comparatively small, confined to the low lands, and chiefly in the volcanic region near the centre of the island.
The surveyor-general issues also " sectional maps " (1:190,000 and 1:40,000) and so-called " Standard " topographical maps for the thinly peopled west, on scales of 1:250,000 and 1:500,000.
The northern and western provinces of Cambodia which fall outside the densely populated zone of inundation are thinly peopled; they consist of plateaus, in many places thickly wooded and intersected by mountains, the highest of which does not exceed 5000 ft.
In the hill tracts and the marshy depression of the Ob they are unbroken, except by the bald summits of the loftier mountains (goltsy); they have the aspect of agreeable bosquets in the Baraba steppe, and they are thinly scattered through south-eastern Transbaikalia, where the dryness of the Gobi steppe makes its influence appreciably felt.
Marryat's first attempt was somewhat severely criticized from an artistic point of view, and he was accused of gratifying private grudges by introducing real personages too thinly disguised; and as he attributed some of his own adventures to Frank Mildmay he was rather shocked to learn that readers identified him with that disagreeable character.