DIGGING UP THE PAST

New Zealand Listener, Volume 20, Issue 511, 8 April 1949, Page 6

DIGGING UP THE PAST

A ONE fine morning, a few weeks ago, three members of the New Zealand Broadcasting Service set out from Christchurch to visit the Pyramid Valley "moa-swamp" near Waikari, in North Canterbury. Molly McNab, of 3ZB, was collecting interviews for her Women’s Hour, while Godfrey Wilson, of 3Y A, and Ashley Lewis, recording engineer, were after material for a feature-programme which will have its first broadcast from 3YA on Tuesday, April 12. It is probably true to say that none of them was completely prepared for .the story that was unfolded at the swamp. We reproduce it here as told in outline by Roger Duff, Director of the Canterbury Museum; but for the full story of just what it feels like to be "digging up the past" readers should tune in to Station 3YA Christchurch, at 8.26 p.m. next Tuesday. :

HE first of many swampgraveyards of moas was discovered in 1866 at Glenmark, North Canterbury. Julius — von Haast, then Provincial Geologist, was collecting for the Canterbury Museum. A selection of the bones of about a thousand moas was taken in four horse-waggons to Christchurch, and when the Museum opened in 1870 with von Haast as its first Director it possessed a then unrivalled set of articulated moa_ skeletons. In fact, the Museum got its start in life from this early find; by exchanging skeletons the energetic von Haast was able to build up the world-wide collection which was the objective of all Victorian museum directors. The second Canterbury discovery was at Kapua, Waimate, when _ from a swamp only 30 feet long by 20 wide the remains of some 800 moas were recovered. ? In both these areas bones were found like driftwood, in disordered masses, An early photograph from Wai-

mate shows the different types stacked like cord wood; from the respective piles the scientists of the day fabricated their numerous species of moa. Pyramid Valley is about 12 miles due west of Glenmark, between Waikari and Hawarden. Joseph Hodgen’s farm lies in the valley, and the swamp is not very far from his house. One day ‘in 1937 one of Mr. Hodgen’s horses died. With due ceremony a grave was dug in the soft ground of this, three-acre swamp and at the bottom were unearthed the three articulated bones of a moa’s leg; they measured six feet, to the hip, Mr. Hodgen recognised the remains for what they were, but at the time was more concerned about the burial in progress; so the bones lay in his woolshed until a friend, David Hope, happened one day to see them. Mr. Hope was a talented amateur naturalist, and realised immediately that the bones were part of the skeleton of a single moa. He knew how rare individual skeletons were, so took the bones down to Dr, R, A. Falla at the Canterbury Museum. This

was in 1939. Early that year the Museum sent an expedition to inspect the swamp. David Hope went with it and, as an old gum-digger, was able to use his spear to locate the three skeletons, which were the result of the first day’s work.

No Dusty Death At Gienmark and Kapua the bones may have been carried into the swamps by water; but there was something new about Pyramid Valley-the birds had died in the swamp and their bones lay in separate and distinct heaps..And not only bones: in many cases the complete gizzard-contents were found standing out in the yellow lake-deposit, looking for all the world like discarded plum-pud-dings (with stones instead of plums). The pebbles which had been swallowed by the largest moas were up to four inches long. Amongst the vegetation over which the birds had been browsing or grazing, and which had formed their uncompleted last meal, could be recognised the seeds of trees like black pine and ngaio, and of shrubs which included the Carmichaelis. In one case the diet would appear to have been tussocks and coarse grass, in another the twigs and berries of a shrub. The first two seasons’ work produced the previously unheard-of total of 50 individual moa-skeletons, while excavations resumed since the war have yielded another 89. This large number of moas comprised only four distinct types whose bona fides, from the condition of the excavation, were above suspicion. Of these only one was alive when. the earliest moa-hunter Maoris first arrived about a thousand years ago. The other three types, including Dinornis Maximus (which reached heights of between 10 and 12 feet) died out long before the arrival of man. This explodes the popular belief that the bones in the swamps are those of moas which were fleeing before fires lit by the early Meoris. An even more telling objection to this theory can be found at swamps such as Glenmark and Kapua, where it would have been physically impossible for hundreds of moas to have entered such a small place all together. The simpler explanation, accepted by modern investigators, is that the swamps were naturally treacherous places which trapped unwary birds. The Pyramid Valley swamp shows how this happened. g Moa in Aspic The top 18 inches of black peat represents the stage when the silty lagoon waters became solid and grew a dense mat of swamp tussock and other vegetation. Walking on this surface of the swamp is rather an uncanny experience, and frightening if you're allergic to earthquakes. Below the comparatively thin peat crust lie four feet of quivering yellow jelly, which tells the story of a prolonged cycle of wet conditions during which the lake-waters deposited fine clay silt, vegetation, and great quantities of lime. Some’ of this lime was sluiced down from the limestone hills, but as much or more resulted from the death of millions of tiny limestone-bear-ing organisms. To this, in due course, the decaying carcases of moas added their quota of organic material. The moas broke through the peat crust at a period when it was much softer than it is to-day and sank down into the then viscous yellow morass; to-day that layer has "jelled" and reminds you rather of spanish cream. From it the bones protrude, brilliantly yellow, and

as fresh looking as if the birds had died a hundred years ago. However, they must certainly have died over two thousand years back, and death could have occurred as many as 20 thousand years ago. Within its layers the yellow mass also imprisons perfectly recognisable leaves, seeds and bark-covered branches of a now-vanished forest. Also present, but invisible to the naked eye, are millions of indestructible grains of the pollens and spores which drifted over the area every year. From these, and from the shells of tiny water-snails left behind in each silt-layer as the water rose, it may in time be possible to trace quite a reliable history of the swamp, including the particular period of time at which moas and other animals were trapped in it. Of these other creatures flightless birds are most conspicuous. They include an extinct goose (Cnemiornis); Aptornis, a giant relative of the woodhen, and larger than a turkey; and even the kiwi, which is still with -us. Birds of Prey Too Of the flying birds, the remains of ducks and pigeons can be easily accounted for; one must have died on the surface of the swamp, and the other have tumbled from its tree perch in the forest beside the lake. But an intriguing air of mystery surrounds the presence, of the bones of Harpagornis, a powerful eagle as large as the wedgetailed species of Australia, to which it is closely related. The skulls of these, six inches from base to down-curved tearing-beak, have been found close to the remains of their possible prey-the moas. Alighting, either to feed on a struggling bird or its carcase, the eagle may have been trapped and carried down with its victim. While the possibility of finding a moa’s egg was always present, the only egg found was in 1940, after only 20 skeletons had been recovered. Unlaid, but fully-formed in the body of a small emu-like moa, this egg had floated free after the decomposition of the body, collapsed into hundreds. of fragments which had _ been _ pre-

vented from floating away by the broad, plate-like breastbone. When found in the yellow deposit these fragments were piled like saucers in a compact mass. The laborious task of reconstructing the egg was accomplished by the late Edgar Stead. In the past the Canterbury Museum was assisted by the cheerful but sporadic efforts of voluntary workers. During the war little work was done; but interest in Pyramid Valley was revived early last year when Dr. Robert Cushman Murphy, of the American Museum of Natural History, New York, visited the

site. The first systematic excavations began _ in February this year under the supervision of Roger Duff, newly appointed Director of the Canterbury Museum. In place of the earlier, scattered pits, a continuous trench was driven into the swamp, and an area eight yards wide by 48 long carefully worked through. For this work the Museum has employed two experienced diggers: James Eyles, who gained his digging experience as the discoverer of the moa-hunter camp at Wairau Bar, Marlborough, and R. J. Scarlett, a veteran of earlier Waikari expeditions. Within the six weeks before the NZBS team visited the site these two added 60 moa skeletons to the total, as well as three perfect specimens of Aptornis, the first remains of Harpagornis, and the Tuatara. Their skill as excavators was warmly praised by Dr. Murphy, who observed that "it takes an archaeologist to excavate a deposit of fossil birds. . . ."

This season’s excavations have attracted many visitors, including 60 deélegates from the Seventh Pacific Science Congress and, more recently, members of the Board of Trustees of the Canterbury Museum, and the Association of Friends of the Museum. And what about the owner of the swamp, and his family? They have remained unperturbed throughout. To Joseph Hodgen’s generosity the Museum owes this unique opportunity of increasing our knowledge of the period between the retreat of the glaciers and the arrival of man.