The springs, geysers and steam vents are scattered over it in the most irregular fashion.
The geysers and other hot springs are due to the same causes as the active volcanoes, and the earthquakes are probably manifestations of the same forces.
The volcanoes have long been extinct, but the diminished energy now causes hot springs and geysers in all parts of the plateau, about loo in number.
The silicious matter has also built up around the springs and geysers cones or mounds of considerable size and great beauty of form.
The district abounds in geysers, springs, mud volcanoes and other phenomena; some of the waters have petrifying powers, and some of the springs are vividly coloured.
Fine lakes and waterfalls, innumerable pools, in temperature from boiling-point to cold, geysers, solfataras, fumaroles and mud volcanoes still attract tourists in large numbers.
Certain springs and geysers lose some of their energy at intervals, while others gain; certain geysers have become quiescent, but some new ones have been formed.
But the low temperature causes the moisture-laden winds to deposit here greater quantities of rain and snow than in the semi-arid regions below, which not only promote the growth of vegetation, but cause the activity of the springs, geysers and waterfalls.
Various geysers and cold and warm sulphur springs are found in the centre of the residency, and on a ridge of the Karang Mountain is the large crater-lake Dano, a great part of which was drained by the government in 1835 for rice cultivation.
It was once generally supposed that the Pliocene epoch in Nebraska was distinguished by the activity of geysers; but the so-called geyserite " now known commonly and correctly as " natural pumice " and " volcanic ash," which is found in the Oligocene and later formations, has no connexion whatever with geysers, but is produced by the shattering of volcanic rock.
Two miles south of Rotorua is another native village, Whakarewarewa, where there are geysers as well as hot springs.
It is in association with this field of extinct volcanic activity that a remarkable group of geysers and hot springs has been developed, from which the Yellowstone river, a branch of the Missouri, flows northeastward, and the Snake river, a branch of the Columbia, flows south-westward.
Its waters are mainly collected from the rainfall upon the plateaux, and from the hot springs and geysers, most of which are within its drainage area.
The strange phenomena of this region were known to some of the Indians; they were discovered by John Colter, a member of the Lewis and Clark expedition, in 1807; the region was visited by James Bridger before 1840; an account of the geysers was published at Nauvoo, Illinois, in The Wasp, a Mormon paper, in 1842; Captain W.