Identifier: transactionsofro68roya (find matches)
Title: Transactions of the Royal Society of New Zealand
Year: 1868 (1860s)
Authors: Royal Society of New Zealand
Subjects: Science
Publisher: Wellington, N.Z. : The Society
Contributing Library: Brigham Young University Hawaii, Joseph F. Smith Library
Digitizing Sponsor: Consortium of Church Libraries and Archives

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image:
ms the supposition, and shows that itbelongs to the trachytic class of volcanoes. The shape of the crater issingular, its length being more than twice its breadth, and the northernpart being divided into two, by a ridge running from the edge of the cratertowards the centre of the island, and directed nearly to the boat harbouror that point where the wall of the crater is lowest. This configurationis probably owing to there having been two craters, the southernmost ofwhich was the last m activity, and filled up the northern one with ashes;and the two valleys have been subsequently scooped out by sub^rialdenudation. The direction of the dividing ridge, and the termination ofthe north-western valley in a narrow gorge prove the correctness of thisview. Nearly the whole of the island is composed of trachytic tuffs andbreccia generally either white, or of a pale yellow or violet color, andenclosing here and there, fragments of trachyte and obsidian. These ARID ISLAND 4 incites =1 •m/^le/.
Text Appearing After Image:
Ca.ja^J£iato7t. cUZ: J.IIucAanan liiA. Jrinleii al lie (nn. CovjCilk Prtai. iy t/.£a.rl. 165 tuffs are arranged in tlie cliffs that formed the wall of the crater,more or less horizontally, although of course much confused in places,and are but little intermixed with lava streams. To find these latter,we must go to the adjacent coast of the Great Barrier, about three milesdistant, where, at the south side of Wangapoua Bay, we see thick bedsof trachyte, and trachy-dolerite, interstratified with tufa, dipping awayfrom Arid Island at an angle of 35°; and farther inland, on the top ofthe dividing ridge of the island, we find tufa and agglomerate, most pro-bably derived from Arid Island, at an elevation of 1550 feet from the sealevel. Now, these facts lead to some interesting deductions, which bear onone of the great questions of the day, in Geology, viz. :—Are volcanoesconnected with a central fluid interior of the earth, or are their lavasderived from comparatively shallow depths bel

Note About Images