The N.Z. Times (PUBLISHED DAILY). SATURDAY, JANUARY 20, 1906. ISLAND ARCHITECTS.

New Zealand Times, Volume XXVIII, Issue 5802, 20 January 1906, Page 4

The N.Z. Times

(PUBLISHED DAILY). SATURDAY, JANUARY 20, 1906. ISLAND ARCHITECTS.

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Tho origin of the Pacific atolls is a matter about which thorn lias boon much scientific dispute; but by the simple process of boring a hole down through a selected coral Island, Mr IV. J. So! las, Professor of Geology at Oxford, lias satisfactorily settled which of the conflicting theories is geologically sound. Professor Sollas, in his justpubliahed book, ‘Tho Ago of tho Kartli,” devotes a largo amount of attention to tho expedition to the cowl island of Funafuti, to tho north of Fiji, .which succeeded in furnishing to this perplexing problem a satisfactory solution. Tho expedition was arranged by tho British Association, and help was obtained from tho Government of Near South 'Wales. Tho two rival theories set at rest by tho boring experiments at Funafuti were Darwin's famous theory propounded as tho result cf his investigations during the voyage -f the Beagle, and tho theory put forth by Sir John Murray.

Tho islands of t.lio Pacific, which rise from an ocean-floor submerged at an average depth of over a thousand fathoms, are, says Professor Sollas, of three kinds. Some of them, like Kow Zealand, appear to bo tho surviving fragments of a lost continent sunk beneath tho waves. Olliers, like tho Sandwich Islands and Fiji, represent volcanic cones which rise from tho deptlis of tho sea. “In addition to those, however, there exists a tliird and strango kind of islands, restricted to tho torrid zone, and known to tho daring mariners of the Kiizabethnn period as ‘low’ islands . . . tho loftiest summits of most not exceeding tho insignificant height of ten foot.’’ These are the true coral islands. All arc apparently constructed from tho same model. A few hundred yards from tho coast tho sides of tho island descend almost precipitously to great depths, tho island itself being represented by a. hollow ruin enclosing a shallow inner lagoon, often of vast extent. In probing for tho origin of these atolls, it was found that they were constructed solely of ono kind of rock, a limestone, which was identified as tho product of tho coral insect. Put tho simple explanation tliat these islands were tho work of reef-building corals was apparently shattered by the authenticated fact that reef-building corals work only within tho surface waters of tho ocean. They cannot livo in deep water. Yet tho foundations of the coral island are laid on the fathomless floor of tho Pacific. How did tho coral insect begin his work in depths fatal to bis existence? And bow did tho atoll raise itself to the surface? Darwin's theory was striking and simple. Ho assumed a vast continental area —the lost Pacific continent — slowly being submerged beneath tho waves. As the summits of the land gradually disappeared beneath, tho water tho coral insects working in shallow waters surrounded thorn with reefs, till, when all trace of tho original land-summit had disappeared, its site was occupied by a central lagoon, encircled by tho ring of ooraf reef. Sir John Murray, however, held that deeply-sunken summits might have been raised sufficiently near tho surface for corals to work by tho incessant downward rain of inrinuto organisms from tho surface of tho sea. It was hero that Professor Sollas suggested a practical tost, by means of deep borings, of the materials that composed tho foundations of atolls. If Darwin’s theory was correct, the core would ho found to contain tho remains of reef-building corals as far down as tho reef extended. If Sir John Murray’s hypothesis was true, tho base of the atoll would bo composed of a layer o£ chalky ooze upon the floor of the ocean. The boring nas tarried

down to a depth of over one thousand feet ; and the fuels triumphantly proved the truth of Darwin's inspired It was found that the limit of coral-ieef building does not extend below forty-five fathoms from the wirfaco of the sea; while no rock other than coral-reef took was encountered in the haring. ami the strnetin es met with were such as excluded Sir John Murray's theory. Professor Sollas, therefore, comes to this conclusion;—“'We must admit that this atoll at- least has boon formed during a .subsidence of the foundations on which it- rests, a subsidence which must amount at least to 877 ft.”

Thus, according to Darwin's now substantiated theory, every atoll stands a.- the mark of the site of a vanished mountain top. Hut the atolls of the Pacific, as Professor Sollas points out. are so numerous that if one imagines all tlie iediuids they icpresent as sumnniiKsl hack from the vasty deep and restored to their original positions above the sea. ■■they will constitute a very considerable tract- of'land, and this situated in the very middle of the Pacific Ocean.” So that the theory of an ancient Pacific continent is finally established : and we are brought to the conclusion that even continents and ocean basins arc subject, to the mutability am! lack of permanence that arc the heritage of all things in this lilc. Ihe coral specks that dot (he Pacific nro but as the tops of columns set up to mark the cite of th(> vast buried Pacific continent of which New Zealand is possibly the last .surviving peak