Page:Transactions and Proceedings of the New Zealand Institute - Volume 1 (2nd ed.).djvu/476

Rh how many gradations there are, if measurement be taken as the sole criterion.

Mr. Travers said that where the bones were found mature, Dr. Haast seemed to have determined their species by their relative proportions. Supposing it should be ascertained that the test was not a good one, Dr. Haast must be absolved from all blame, seeing that he had followed Professor Owen.

Mr. Mantell had not considered it necessary to state that he merely wished to remark that Dr. Haast showed great courage in endeavouring to determine species upon no other data than (what he took the liberty of considering) the very unsatisfactory test adopted by Professor Owen.

2. "On Indications of Changes in the Level of the Coast Line of the Southern Part of the North Island, as deduced from the Occurrence of drift Pumice," by J. C. Crawford, F.G.S.

Mr. Crawford remarked that pumice, having a small specific gravity, floats in water, and in the rivers flowing from the volcanic plateau in the interior of this island it may be seen descending in great quantities and at all hours towards the sea; when there, it is of course liable to be washed up at any point of the shore, and if there is no cause again to carry it away, it necessarily remains stranded.

Pumice is found on the flats in the Peninsula, near this city, at a height of about eight or ten feet above the present high watermark. He had not observed it on any of the coast terraces, consequently it is probable that the land had attained within ten to twenty feet of its present level before the volcanic chain sent pumice to the sea; and this will give an age to the present coast line, or to one from ten to twenty feet lower (supposing a steady rise of the land), enough to satisfy a very ardent lover of antiquity.

He concluded by saying, "It may therefore be held that the probabilities are against any great oscillation of the present sea level in this part of New Zealand since the commencement of the vast period which must have elapsed since the central volcanic group of Tongariro and Ruapehu (and Mount Egmont inclusive) began to send down pumice to the coast."

Dr. Hector said that pumice was a mechanical variety of obsidian, the most perfectly fused product of volcanic eruption, and did not indicate any particular era in a volcanic eruption, or elevation of a chain of mountains, as Mr. Crawford seemed to require for his theory. The whole of the eastern shore of Lake Taupo had been formed by wind-blown pumice. Along some of the rivers that had cut through the slate rocks on their way to the sea at Hawke Bay, there were terraces with pumice clinging to the sides of the valleys 400 feet above the water, showing clearly that the