FOOTPRINT IN THE "ROCK" OF TIME

Auckland Star, Volume LXXI, Issue 165, 13 July 1940, Page 2 (Supplement)

FOOTPRINT IN THE "ROCK" OF TIME

8y... A. W. B. Powell

attention was recently drawn to a report from an East Cape correspondent of footprints of large extinct creatures in rocks from Te Araroa, East Cape, which were stated to be those of either a Megatherium or a Labyrinthodon. Now, apart from the very doubtful evidence afforded by alleged footprints, the possibility of either of these creatures ever having occurred in New Zealand is so extremely unlikely that it is virtually an impossibility. Megatherium was a mammal, the largest of the ground-sloths—an extinct group related to the modern tree sloths. They belonged to the very recent Pleistocene period and occurred chiefly in the Argentine, but were distributed elsewhere in South America, and Texas and Xew Jersey in North America, with allied smaller species in the West Indies.

Now, Could They? When we consider that in the Pleistocene period the geography of the land masses and oceans were with the exception of small coastal modifications essentially as to-day, then the impossibility of finding a Megatherium in Xew Zealand becomes at once apparent, for how could a lumbering ground creature as large and as massive as an elephant have crossed the vast Pacific? Nothing less than the slave of Aladdin's lamp could have achieved this. And so with the alternative conjecture of Labyrinthodon, representative of a group of ancient large amphibians that lived in Triassie times some 190 million years ago. They were distributed mostly in Germany, England. Nova Scotia. Kansas, South' Africa and in Fast India, having developed on the continental land masses. It would require more convincing evidence, than alleged footprints to claim Labyrinthodon as once living in remote New Zealand, although the possibility is not quite so impossible as with the suggestion of Megatherium, for, after all, we have ou.- tuatara—the sole living member of an ancient reptilian order, that elsewheYe died out over a hundred million years a«o. Isolation a Factor. Isolation in the past has been a great factor in determining the geographic distribution of the animal and plant types of to-day. When the mammals became ascendant in the early Tertiary it was natural that they achieved their greatest development and distribution over the older continents. Subsequently Australia became detached at a time when mammals had progressed only as far as the primitive marsupials. On the older and larger continents ■na-sses mammals continued their evolu ion through stress of competition, but n isolated Australia, free from thai ntense competition the marsupial type prevailed, and so to-day we find that ■ontinent efficiently populated with liarsupial "roups of which the kangaroo is best known. New Zealand, however. was isolated from before the evolution of the mammals, and so these creatures are absent from our native fauna, except for two small bats, which could have reached

here by some favourable chance and the Pacific rat, which was, no doubt, introduced by the early Maoris. In the district cretaceous period, during the age of great reptiles, Xw Zaland was more fortunate and did share in some of the massive reptiles of those remote times. Remains of no land species have been discovered, howeVer, only such

marine types that were world-wifeii distribution, having been capabja viife grossing -wide "of ocean. tS_ ■■ . ..: i.~ ~ -" * ■-.- <£?*>; Ffrrf G t «/ Remans Mi Our firat giant reptilian remains' *er* discovered in 1861 in a ravine on one of the tributaries of the Waipara River'Sfc North Canterbury. Since that Umt thirteen distinct species of these ancient reptiles have been discovered, including species of the well-known plesiosaurus and mosasaiirus, as well as a dktinctta type which was named maukaurus. Not having seen the Te Araroa impressions I am not in a position to state just" what they represent. Similar accounts in the past, however, have proved to' have originated from natural concretionary structure, which sometimes assume quaint shapes, often suggestive of reptilian and mammalian remains. Once I had great difficulty in persuading an enthusiast that some natural elliptical concretions were not as he maintained the fossilised "knee-caps" of an extinct dinosaur.