The White Terrace at Rotomahana.
4. “A Descriptive Account of the White Terrace at Rotomahana,” by J. Martin, F.G.S.
This paper contained a series of observations and measurements taken at Rotomahana in November, 1883, and November, 1885, giving the most minute and careful details of the structures lately known as the White and Pink Terraces, and of the phenomena of thermal activity there exhibited.
The result of these observations was in favour of the theory that the activity of the Terrace geysers had been gradually increasing; having been in their initial form steam vents, which had decomposed the tufaceous rocks into felspathic mud and clays, which with increasing activity became converted into a silicious cement; the fundamental structure of the Terraces being due to the deposit in a plastic condition of the material removed from the cauldron, subsequently indurated by the percolation through the mass of the intermittent silicious overflow.
The paper was illustrated by a series of photographs, taken and prepared by Mr. Martin, which were afterwards exhibited by lime-light.