NATURE NOTES.

New Zealand Herald, Volume LXI, Issue 18771, 26 July 1924, Page 1 (Supplement)

NATURE NOTES.

A CLASSICAL MORAINE. S» J. DJOTSTMOiTD, F.L.S.. T.Z.B. Settlers in the Waihola district, O'tago, in the early seventies, used for road metal and house foundations some boulders that formed part of a vast classical moraine, transported and deposited by, probably, Pleistocene glaciers in • New Zealand's Glacial Period. The boulders rested near a road level between Waihola and Otokaia. They apparently, were transported by the glaciers from mountains on the west side of the Taieri Plain. Professor J. Park, making his headquarters at Henley, has made a particular study of that great moraine. He found that slopes of ridges that front the main road, and slopes that descend to Manuka Gully, are occupied completely by slipped morainic ground. The slias in many places extend from the summit of the ridge to the level of the plain, a vertical height of 400 ft.. Following to their source many angular blocks of micaschist, Professor Park found that they had come from close to the summit of the ridge.

Between Waihola and Otokaia, the Taieri moraine forms hills from 250 ft. to 700 ft. high. The lower division . of. the moraine consists of a 'succession of red clays, gritty and sandy clays, and beds of water-worn gravel, which usually contains a large proportion of small angular fragments of mica-schist. The moraine, in places, has a thickness of 1500 ft., and it may be traced for a length of about twenty-two miles and a width of from one mile to three miles. It roaches its northern limit at Saddle Hill, but small areas of glacial till—stiff clay formation, or boulder-clay—occur in the liaikorai Valley, particularly at Fernhill Coalmine, Abbotsford, and Burnside. Professor Park states that the moraine at Abbotsford is a typical example of glacial till. The material consists of peaty clays that contain moa bones, usually much decomposed, yellowish-brown clays that contain bouldery gravel, and clays with a confused mass of boulders.

On the evidence collected, Professor Park expresses a strong opinion that that immense glacier was a continuous icesheet, not a series of valley-glaciers. It descended from a distant mountain divide in Western Otago to the present coast line, occupying the Taieri and Tokomairiro Basins, from Dunedin to the Clutha, and representing a continuous iceface more than forty miles long.\ Debris left in its track is evidence that it strode over the coastal range on its way to the sea. "From Moeraki to Oamaru, and north to Timaru," Professor Park writes, "the surface of the land everywhere bears the impress of erosion by ice. Nobody can view the landscape, with its. beautiful smooth contours and domed and truncated crests, without being impressed with, the small part erosion by rivers and streams has played in modifying the ice-worn surfaces of New Zealand's Glacial Period."

It is forty-eight years since Mr. J. T. Thomson, chief surveyor of Otago, and later Surveyor-General of New Zealand, first published the theory that Otago had been covered by a continuous ice-sheet. His theory has been criticised by some Wew Zealand geologists, but Proicssor Park describes Mr. Thomson as "a competent geographer and a' distinguished mathematician." The may have been suggested to him: by evidence of ancient glaciation in Scotland, and the work .of valley glaciers in the Himalayas, Been by- him before he came to New Zealand. There seems to. be an agreement among' those who sppak : with authority that the great h glaciation of.New Zealand was caused by a general elevation of the land., It was 3000 ft., or mora It. flung out the boundaries of this, country hundreds of miles east and south, the southern boundary reaching within about 700 miles of the Antarctic Continent.

There is some difference of opinion as to time of the great glaciers, but all students place them sometime in /ihe Tertiary Era, which immediately preceded the Recent Period. Two epochs of t'ae flaciers are distinguished by Professor 'ark. To the older epoch he ascribes the glacial deposits at Blue Spur, Taieri, and Kaikorai, in Otago, and the great boulder tilL in the Rangitikei Valley, Wellington; to the later epoch ha ascribes valley moraines, glacial dams and drifts in the South Island. In the first epachy according to his conclusion, there was widespread glaciation; in the second epoch, there were immense valley glaciers, which made minor advances and retreats before their final recession to the glaciers' alpine strongholds.

Evidence that in former geological times there was land connection between New Zealand and' South America is supplied by plants and animals now found in both countries. Among the plants the evidence of the yellow kowhai is particularly valuable. The , latest zoological evidence is supplied by a lowly isopod, a member of the order of the crustaceans. are many species of isopods; most of them are small, many live in the sea, others live in finish water, others, including the pillbugSj, live on land. This iso : pod, Ligia Novco-Zealandise, which is another link between the two countries, now far apart, was discovered on the shores cf the Bay of Islands by the United States exploring expedition under Wilkes about eighty-five years ago. Another isopod, collected at Valparaiso, was named Ligia cursor. - Two years ago an opinion was expressed that these isopods belonged to the same species. Dr. C. Chilton, Rector of Canterbury College, who made an extensive study of' New Zealand crustaceans, recently received from the Buenos Aires Museum a female of the Valparaiso isopod, labelled "Ligia cursor." He is unable to distinguish this female from females of Ligia Nova; Zealadiaa, found on the New Zealand coast. If the two species are identical, the title bearing the name of this Dominion, on the laws.of zoological; nomenclature, must be retained, and South American specimens as well as New Zealand specimens must bear it. • -

"Shore isopods arid land isopods," Dr. Chilton states, " carry their eggs in broad pouches under their body, until the young «ire hatched in a form almost the same as an adult,, and it is very unlikely that they could cross large tracts of ocean. The presence of the isopod in New Zealand and South America—it occurs also in Juan Fernandez —is additional evidence of former land connection between those places. ( . A shore amphipod, which lives under exactly the same conditions as Ligia Novas Zealandke, is found on the shores of New Zealand. Chili, and Juan Ferandez."

Mrs. V. E. Calvert, Hillsborough, New Plymouth, reports that she found the cup orchid, Petalochilus calyciformis, among scrub at Strathmore, about 20 miles in' from Stratford. It is about five years since she visited that place, but she states that if the scrub has not been cleared individuals of the species probably grov> there still. The cup orchid, described in this column in May last, is one of the latest additions to New Zealand's list of the Orchidce.' It .has attracted the attention of botahists in the Old Country, and was given a prominent place in an issue of the Journal of Botany, published in London, early this year. Mr. H. B. Matthews was its discoverer. Previously, it was reported from only the M'angonui County, North Auckland. Mrs. Calvert's note shows that this slender plant, ornamented with a tiny ; cup, may be more plentiful than was believed. The fear that it will not be available to students of New Zealand's flora seems to.be groundless. This, in view of the regrettable scarcity of some species of New Zealand birds, the rareness of New Zealand's two frogs, the decrease of the Maori rat> and the extinction of the Maori dog, is very satisfactory. .';.:..", ■'•''■''■ V