Making New Zealand vol 01 no 01: The Beginning
The Chronicle of the Rocks
The Chronicle of the Rocks
Rock strata in a cliff on the Taranaki coast. J. W. Chapman-Taylor
Historians tell us that Polynesian voyagers reached the shores of New Zealand many centuries ago. Precisely when is a matter of dispute; some authorities say they first arrived in the eighth century, others several hundred years later. Yet it is certain that they had been in possession of the land for many generations before the first Europeans touched here in 1642, sailing on again to leave the country undisturbed for a further 127 years. Then followed that troubled period of European contact which ended one hundred years ago with the establishment of British rule and the beginning of organised colonisation.
Thus the historian of peoples, looking back over centuries, generations, and decades, divides the history of New Zealand roughly into periods— first the Maori period; then the period of navigators and other casual visitors and settlers; finally the period of settled European occupation.
But the history of New Zealand—of the mountains and rocks and rivers of this interesting land —goes back infinitely beyond the date when the first voyagers from Hawaiki could have arrived here. Man, indeed, has been in occupation for only a small fraction of time. Through long ages before his coming the land was moulded by rain, running water, and wind; it sank beneath the sea and rose again; it was carved by giant glaciers; it was convulsed by land movements and eruptions; it was clothed by forests long since gone and occupied by strange creatures which have been extinct for millions of years.
This fascinating story is revealed to us by the earth-historian—the geologist—and he, like the historian of men, divides his story into periods which cover, not centuries and decades, but hundreds of thousands and even millions of years.
A fossil shell of Tertiary age. J. Marwick
The origin of these rocks is extremely varied; some were once in a liquid or molten state; others such as sandstones are derived from the worn-down materials of pre-existing rocks; others again like limestones, have been built up from the skeletons of marine creatures. Every rock, if correctly interpreted, tells us something about its history through long geological ages.
But the geologist does not read the book of Nature merely by examining samples of rock. He studies the layers, or strata, of rock exposed in a cliff or in a surface outcrop and from their arrangement constructs a longer and more complicated story. The oldest rocks are at the bottom of the cliff, the youngest at the top; in between are the rocks of intermediate age. In this simple way a time sequence is determined, and the geological column is built up.
Even more fascinating is the way in which the geologist reconstructs the past from the traces or actual remains of plants and animals long since extinct. Some 550 million years ago certain primitive sea-animals, defeated by the intense competition near the surface, were forced towards the shallow sea floor and became bottom dwellers. The relatively inactive life in these new surroundings caused bodily changes, one of which was the inability to get rid of all the mineral salts taken in with food. One way out was to deposit this excess material in the form of a skeleton which kept its shape and solidity after the animal had died. Obviously these hard parts had some degree of permanence and, if buried by sediment, might survive indefinitely to yield their mite of evidence millions of years later.
Maui fishing New Zealand out of the ocean. It is interesting to contrast the Maori legends of the origin of New Zealand with the less poetical explanations given by scientists. This fine sketch was drawn by W. Dittmer.