Transactions of the Royal Society of New Zealand Volume 26 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1894 Excerpt: ...parallel to the length of the hill, along its summit. In breadth the dyke measures about 20ft., and in length about 200 or 300 yards, its bearing being B. 41 N. It is evident that the trachyte lava issued from this dyke, as outcrops are found the whole way from the top to the bottom, and are generally of a vesicular character. If, as Sir J. von Haast suggests, it flowed from a central crater, situated near Quail Island, it would necessarily, like the other rocks of the harbour, present a single face of moderate breadth, and of a tolerably constant altitude above the sea-level. It is possible that the lava flowed from a crater that occupied the position where the Town of Lyttelton now stands. This, however, is highly improbable, as no independent evidence exists of the activity of a vent situated there. No system of dykes has been discovered; none of the other hills enclosing the depression afford evidence of such a vent, while on one side all traces of crater-walls, if they ever existed, have been removed. The very appearance, too, of the hill under consideration gives one the idea that its origin is not the same as that of the others, for, while its surface is, generally speaking, smooth and rounded, and resembles the slopes of Mount Herbert, the others, almost without exception, present that series of sharp, steep walls rising tier above tier that so plainly indicates to the geologist that they are formed of lava-flows lying one over the top of another with a moderate angle of inclination. These considerations, and the fact that a well-defined dyke exists at the summit, must remove all doubt as to whether an independent origin should be assigned to this small system of volcanic products. As the age of the whole system of Banks Peninsula is not yet settled...