Between the higher ranges are many fertile plains and low hilly districts, well watered but comparatively little cultivated in consequence of intertribal feuds.
Ponies are most esteemed from the wetter regions of the east, and the hilly tracts.
The Lepchas are considered to be the aboriginal inhabitants of the hilly portion of the district.
On the west another rough and hilly tract, similar to that which divides it from the Sierra de Guadarrama in the east, separates it from the Sierra de Gata, the westernmost and the lowest of the Spanish sierras belonging to the series.
The real tea (The y viridis), a plant akin to the camellia, grows wild in Assam, being commonly found throughout the hilly tract between the valleys of the Brahmaputra and the Barak.
In Great Britain in the breeding-season it seems to affect exclusively hilly and moorland districts from Herefordshire northward, in which it partly or wholly replaces the common linnet, but is very much more local in its distribution, and, except in the British Islands and some parts of Scandinavia, it only appears as an irregular visitant in winter.
Geologically Sardinia consists of two hilly regions of Pre-Tertiary rock, separated by a broad depression filled with Tertiary deposits.
The city is regularly laid out on a hilly site, on both sides of the Purgatory (or Las Animas) river, near a picturesque canyon and mountain district, including the Stonewall Valley, and at the foot of the Raton Mountains, of which the highest peak, Fisher's (or Raton) Peak (9586 ft.), is 10 m.
Large portions, however, in the hilly centre and in the south-east, are still remote from railways.
The hilly aspect of several parts of the central plateau is not due to foldings of the strata, which for the most part appear to be horizontal, but chiefly to the excavating action of the rivers, whose valleys are deeply eroded in the plateau, especially on its borders.