Report on the Geology Woodlark Island
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REPORT ON THE GEOLOGY WOODLARK ISLAND. Bt EVAN R. STANLEY. c. 10048. NOT TO BE TAKEN FROM t h e LIBRARY, REPORT O F THE GEOLOGY OF WOODLARK ISLAFD. B y E v a n B . S t a n l e y . INTRODUCTION. The accounts of the discovery of Murua, now called Woodlark, appear :to be very scanty and meagre, and much difficulty was encountered in arriving at any information at all satisfactory. Louis Voez de Torres * *§ is credited with being the discoverer of the -Louisiade Archipelago in 1606. Among the first to visit the Archipelago were the French navigators, t who explored some of the islands of the group in the years 1766-1769. Later, in 1793, Bruny-D’EntrecasteauxJ passed through these waters, and the group of islands received his name accordingly, but in these cases no mention is made of Murua. The earliest available information of Murua was the establishment of a Marist mission§ in 1847. It was abandoned in 1852. They were followed by Italian missionaries || the same year, who, like their pre decessors, abandoned it soon afterwards. The geological pioneer of New Guinea is Mr. John McGillivary,H of H .M .S. Rattlesnake, who visited the Archipelago in the years 1846-1850. The only geological data prior to my visit to Murua is that published bÿ H . R. Maguire,** who refers to the occurrence of schists with gold- bearing quartz veins, and what information is to be obtained from the Annual Reports. Some years ago, the man-of-war Woodlark visited Murua, and since then it has borne the name of that vessel. Gold was first discovered in the vicinity of Suloga Bay, at two places almost simultaneously, some fifteen Or sixteen years ago. In June, 1895, Messrs. Ede, Lobb, and Soelberg prospected at Suloga -and Okiduse, situated on the southern coastline of Murua. Good indication of gold was obtained from each locality, and, later on, an abundance of alluvial gold was discovered. At Okiduse, a very rich patch of 500 q z s . was unearthed, being slightly water worn. In December of the same year good alluvial deposits were discovered at New Chum’s Gully, now known as Karavakum, or Boniavat. Karavakum was the first locality on the island in which a large number of men worked, there being at the time 300 or 400 men on the spot. Shortly after this important rush K ulu madau was discovered, and worked for alluvial. Here reefs were first discovered, and extensively worked in or about the year 1900 by the Wood lark Island Proprietary Company and the Ivanhoe Company. These com panies subsequently sold out to the Kulumadau (Woodlark Island) Gold Mining Company Limited, which company is working the greater part of the lode at Kulumadau at the present day. * Animal Report, B.N.C. -j- “ Voyage autour du monde,” par La Bondeuce et La Flute L’Etoile, 1766-1769. j “ Voyage de Bruny D’Entrecasteaux, 1793.” § “ Histoire de la Premiere Mission Catholique au Vicariat de Melanesie, by Verguet. I| Annual Report B.N.G. 1890-1891. •if Ibid. ** “ Impressions of a Year’s Sojourn in B.N.G.,” by H. R. Maguire. 0 . 10048. 2 Soon after the Kulumadau rush, McKenzie’s Creek, situated inland about 6 miles from Kulumadau, was discovered. Several thousand ounces were obtained in a very short time , This locality undoubtedly holds the record for the greatest quantity of alluvial gold yet obtained on the island. Simultaneously with McKenzie’s Gulley, Eusai, situated about 3! miles from Kulumadau, was discovered. In the creeks about this locality much gold was obtained, and although some o f the alluvial areas have been worked several times, there is still a considerable quantity of the native metal to be extracted from them. Within recent years, several payable reefs have been discovered in the neighbourhood of Busai. Besides the above-mentioned localities, there are other places which have yielded larger quantities of alluvial. Such are Sinkurai, situated on the head waters of the Sinkurai, and Munkiai River, Reilly’s Creek, about i mile from Busai, and Wonai and the Ben, situated on the southern portion of the Okiduse Range. Much of the foregoing information was obtained from some of the oldest residents, together with the available data from, the Annual Reports. The examination of Murua extended over a period of four and a half months, during which period a geological map of the island was prepared, and the principal mining centres examined and reported upon in some detail. Owing to the impenetrable forests, swamps, continual rain, and rough country, progress was somewhat impeded. There are no means o f locomo tion, except faire la ronde, and, where this was impossible, a whaleboat or native canoe was resorted to. Many o f the conclusions arrived at have been based largely upon field observation. I regret to say that, as this section of the Mines Department has just been instituted, the amount o f detail required in a report o f this description will be wanting. Only a limited amount o f laboratory work has been done, thus making this report, in a sense, incomplete. PHYSIOGRAPHY. Area and Position.— The island o f Murua, with, its adjacent islets, is situated approximately between longitudes 152, 25' E., and 153, 5' E., and latitudes 8, 55' S., and 9, 15' S. It has an area of about 370 square miles, of which there are about 50 square miles of mineral bearing country. Communication.— The only means of communication with the outside world are when the s.s. Matunga and the s.s. Mindoro arrive, the former once in six weeks, the latter once a month. These steamers connect with the other Papuan ports, and with steamers from Australia and eastern waters. It is unfortunate that there is no telegraphic^ communication, but such inconvenience can be obviated by the installation of a wireless telephone station. There are no suitable vehicular roads in Murua. The mining centres are connected by tracks suitable in part for pedestrian and horse traffic. Road construction would not be difficult, as very little grading is required, and there is stone suitable for the purpose in the localities through which the roads would pass. Tomography.— Murua has a linear extension o f 44 miles, and trends in a W.N.W. and E.S.E. direction. Its width is irregular, varying from 5 to 10 miles in the western portion, and from 10 to 20 miles in the eastern and middle portions. The principal harbors are Buyuesi, Guasopa, Suloga, Wonai, and Kwaipan Bays, in which there are anchorages for 3 deep-sea boats, the latter being the present port of entry. The island is surrounded by numerous and dangerous coral reefs, and a few smaller islands. In two or three localities portions of the main island have been detached by small canal passages, which, are either wind or water gaps, as, for example, Nasai and Monvauva, situated respectively on the southern and western portions of the island. The Mellin Group, Nubara, lone, Panamana and Ginara Islands, &c., are low-lying coral islands on the exterior portions of the reef. The mountainous country is restricted more or less to the central north eastern portion, where there is a range of hills trending north-east and south-west, with an altitude of about 1,000 feet. The south-west extreme reaches a height of 1,300 feet at Suloga Hill, and abruptly terminates at the north-east extreme in Kabat, which is 740 feet. Apart from the Okiduse Range, and situated to the westward, is the Kulumada.u Hill, which has a more northerly trend, and is low-lying swampy country, with numerous hillocks of coral limestone. The limestone and swampy country is met with in the western portion, o f the island, but on the northern coast line and eastern portion there are high cliffs and hills, with a few elevated inland swamps. Near the ranges, and overlying the coral limestone, there are numerous alluvial deposits which have been and are being worked for gold. Rivers and Creeks.— Although Woodlark is such a small island it possesses several rivers which are at all times plentifully supplied with water, owing largely to the continued and excessive rainfall. These take their sources in the Okiduse Range, and are fed by numerous streams both in the high and lowland country. The Muniai River is the largest, and flows irregularly in a westerly direction through the coral country, and meanders in the swampy mangrove country to the west of Karavakum., Use is made of this river, as it is navigable as far as the Karavakum bridge. Of the other rivers the Sinkurai, Munkiai, and Lafuai flow easterly through similar country, and are partly navigable. To the westward there is a series of creeks which drain the swampy country inland. Water Supply.—Woodlark is provided with an excellent water supply* the average rainfall being about 15 feet a year. This useful factor,, though always in demand in Australia, is at times a serious inconvenience to mine properties on Woodlark. The rapidly flowing portions of the rivers in the vicinity of the mining leases could be in some cases effectively used for power. Climate.— Though situated on the 9th latitude, Woodlark is out of the belt of cyclonic storms. There are two' seasons, one in which the south eastern trades prevail and the other the north-western monsoons, but there is very little difference, as far as climate is concerned, between them. The island is not an unhealthy place to live in, there being little sickness throughout the year.