Stretch Of Sand Research Articles

Problems in atmospheric electricity at Apia, Western Samoa

Determination of influence of height of tide on reduction‐factor of Lagoon‐Station, August 3, 1931All previous determinations of the reduction‐factor for the lagoon‐station at the Apia Observatory have been made either at Watson's Island, about one‐quarter mile east of the lagoon‐house, or in the lagoon southward from the main observatory buildings. The actual places used were in the first case a flat rocky shelf and in the other a flat stretch of sand both of which are laid bare at low‐tide. Since the flat stretches are covered with water before half‐tide, observations have thus been confined to low‐water or thereabouts. It was thought that the rise and fall of the sea‐level with the tide had no influence on the reduction‐factor on account of the concrete platform about eight feet square beneath the collector, which formed a permanent earth‐plane.

The Avonian Succession in the South of the Isle of Man

The Carboniferous rocks described in this paper occur within an area some 8 to 9 square miles in extent surrounding the ancient town of Castletown. The district is coastal and low-lying, a considerable portion being less than 100 feet above sea-level. The highest ground lies north-west of Ballasalla, where a few small tracts rise slightly above 200 feet. The solid rocks are for the greater part obscured by a thick covering of drift, alluvium, or blown sand, and the chief outcrops are on the coast, usually between tide-marks. Most of the inland outcrops are confined to quarries lying west of the village of Ballasalla, to the Silver Burn, and to its tributary the Awin Ruy. The heavy growth of seaweed and the honeycombing of the boring molluscs near low-water-mark render difficult the collecting of fossils, which, in many places, are also partly or totally destroyed by dolomitization, especially near the more important faults. Stretches of sand, shingle, and displaced joint-blocks break the continuity of the beds in the cliffs and on the foreshore, so that direct measurement of thickness is often impossible. The Carboniferous rocks are bounded on the north-west by the Port St. Mary—Arbory Fault, which extends from Perwick Bay to near Ballashimmin (a distance of 5 miles), and with variable throw brings up the Manx Slate Series. Elsewhere on land the boundary is an unconformable or faulted junction with the Lower Palæozoic rocks. A similar junction probably exists a short distance below low-water-mark between the mouth of the

The intrusive rock of Frances Craig, and the teschenite of Ravensheugh

Frances Craig is an isolated rocky area 600 feet long and 400 feet wide, east of Tantallon and about one-third of a mile north-west of St Baldred’s Cradle, and separated from the mainland by a wide stretch of sand, the Ravensheugh sands. The place has not been much studied. It is mentioned in the Memoir of the Geological Survey for East Lothian, 1910, p. 97: ‶A mugearite intrusion occurs on the shore at Frances Craig, . . . but possesses no special interest.″ The Ordnance Survey took but little notice of Frances Craig, only sketching it on the map. The outline was so very faulty that it was necessary to make a proper survey before a good detailed geological map could be constructed. It was then found that the igneous rock was intrusive in sandstone, in a rather complicated way, as a sill, the top and bottom of which can be seen (Fig. 1). There are a few interesting facts. The igneous rock is of a uniform brown colour, with a variable texture, and has suffered decomposition to a certain extent. A microscopic examination proved it to be a teschenite and not a mugearite. It contains a large amount of magnetite and ilmenite, very abundant in some parts. On Frances Craig, especially on the west side, which represents the upper surface of the sill, the junctions with the sandstone are difficult to trace, owing to the great similarity in appearance of the two rocks. There are also fine exposures of

Observations on the geology of Lewis

Lewis, sometimes termed the Long Island, is the largest area in the chain of islands which constitute the Outer Hebrides, and which extend from Barra Head to the Butt of Lewis, a distance of 130 miles. The long tortuous shore of Lewis is mainly a series of high precipitous cliffs penetrated by sea lochs, or breaks, where stretches of sand or shingle and boulder beaches add to the natural attractions of the island. Many islets begird the shores and afford sanctuary to birds and seals. The surface of mid and north Lewis, for over 300 square miles, is an extensive stretch of bog, moorland, and loch, leaving a cultivated fringe bordering the sea, inhabited by crofting communities. A prospect from the central ridge of the northern moor does not disclose a rock vestige for many miles, and even the streams flow between deep banks of peat, barely disclosing the glacial till. Hilly country in Lewis is found in the high plateau ground of the Park district to the south-east, a central tract from the Cleisham Mountain northwards to Roineval, west of Balallan, and the Uig Hills to the south-west; while a few groups and isolated hills rise from surrounding bogs. The old crystalline Lewisian gneiss, of which the island is principally composed, shows a primary north-west strike, but upon this has been superimposed a later terrestrial crust movement which produced a north-north-east strike with dips to the south-east. This latter foliation is predominant from east to west of Lewis. The

The Rouna Falls of Papua

boats. We ourselves crossed in leather boats; the crossing took one and a half hours. When nearing the south bank we had to work our way through many sandy islands, which delayed us. In winter these islands are part of a wide stretch of sand, and the crossing is much shorter. We made a delightful camp on mrf under willows at the village at To, or Chi-te Sho. The people had never seen a European, and were very curious to see what we were like. Our ponies were crossing in a wooden boat, which had to go for a long way down and be pulled up past the islands to the end of the Nong La spur, which was the only place where they could be landed. They did not reach there till the next day. On August 22 we marched 20 miles up the south bank to Gongkar Dzong. From a spur of the Nong La, 400 feet above the river, we had splendid views of the broad valley both up and down stream. We descended and continued up the flat valley. There were numbers of Bar-headed geese on the river-bank, which were so tame that I was able to get some photographs of them. The next day I visited the Dzongpen of Gongkar. In 1904 he had been one of the Garpons, the officials at the Gartok trade mart in Western Tibet. We had met when I went there with the late General Rawling, Colonel Ryder, and Colonel Wood of the Survey of India. Six miles from Gongkar we crossed the Yab La, a spur about 500 feet above the river. At the end of this spur is the ferry of Chaksam, where the expedition under Sir Francis Younghusband crossed the Tsangpo in 1904. We were now on well-known ground. We camped the night at Singma Kangchung, whence we telephoned to His Holiness the Dalai Lama to tell him we had rejoined the main road. When in Lhasa the Tsarong Shape had asked me about the possibility of using motor boats on the Tsangpo, and at his request I measured the velocity as well a? I could in some of the more rapid places and found it to be between 5 and 6 miles an hour. We returned to Gyantse by the usual road vid Nangartse, the Karo La, and Ralung.

Notes on the Hummell Rocks, Gullane

The Hummell Eocks are situated on the shore 1¼ miles west of Gullane Station, quite close to Gullane Point, on its eastern side. The annexed map, Fig. 1, enlarged from the one-inch Geological Survey map, shows the character of the ground. A prominent feature in the landscape is the sill of analcite dolerite named Corby Craigs which runs up the hill in Whin Park. This sill was proved by boring to be about 140 feet thick1 at one point. One object of this paper is to show that this dolerite sill is continuous with the intrusive mass known as the Hummell Rocks, seen on the map a little to the north-west of Corby Craigs. The second object is to point out the occurrence of peculiar dykes, apparently of sedimentary matter, in the Hummell Rocks, and to suggest their probable origin. On examining the base of the sill of Corby Craigs at the spot where it runs down to high-water mark, it will be noticed that the dolerite is markedly different in character from that composing the main sill (see Plate XI., Fig. 1). The change is rather sudden, and the rock has all the appearance of white trap, while its continuity with the main sill is quite clear. In the Geological Survey map the west end of the sill is marked with a definite boundary line which suggests the termination of the sill at that point, indeed there is a stretch of sand for a short distance before we come

IV.—Wind Erosion on the Coast of Mull

The Ross of Mull is a comparatively low-lying peninsula exposed to the storms and swept by gales from the Atlantic. On these rocky shores are occasional stretches of sand which frequently have been driven inland, forming dunes and patches of blown sand at intervals around the coast. Sometimes the sand is forced up the cliffs and deposited more than 100 feet above the sea, and there are places in the centre of the peninsula where the blown shell-material is quite a noticeable constituent in the soil.