Dec. 31, 1885] 



NA TURE 



205 



by Dr. Leonard Dobbin, a considerable amount of mag- 

 nesia, and thus approaches a magnesian limestone. 



4. Compact fawn-coloured crystalline limestones of a 

 homogeneous texture, in which sometimes reef debris may 

 be observed. These rocks, which are of common occur- 

 rence on the lower slopes of the large island of St. Chris- 

 toval, where they overlie the volcanic rocks of the district, 

 are apparently formed by the consolidation of the ooze 

 found at the bottom of lagoons inside coral reefs. 



5. Foraminiferal limestones, which are hard and com- 

 pact in texture, and are chiefly made up of pelagic and 

 bottom-living Foraminifera, and contain occasionally a 

 few simple corals of deep-sea genera. They contain 

 generally from 75 to 85 per cent, of carbonate of lime, 

 the residue being formed of the common volcanic minerals, 

 siliceous casts of Foraminifera and fine argillaceous matter. 

 These limestones are found at the surface, and in the 

 island of AIu they may be seen to overlie the soft Forami- 

 niferous and Pteropod deposits. 



.Such are the calcareous formations which are of most 

 frequent occurrence in the Solomon Islands. Three other 

 highly interesting rocks came under my notice, but in 

 each case only in one locality. 



((() A Rhynconella limestone. In one of the islets of the 

 Shortland Islands I found a hard grey limestone composed 

 of numbers of Brachiopod, Gasteropod, and Lamellibran- 

 chiate shells, with many simple corals of deep-sea genera, 

 embedded in a calcareous matrix largely made up of the 

 tests of Foraminifera (chiefly pelagic forms). The Bra- 

 chiopod shells belonged to the same species of Rhynco- 

 nella. Mr. Davidson is inclined to look upon it as the 

 same as R. Grayii, a species hitherto represented by a 

 single specimen discovered inthe British Museum amongst 

 other natural history objects from the Fiji Islands (?) col- 

 lected by Mr. J. M'Gillivray more than thirty years since.' 

 The simple corals, as Mr. Quelch informs me, belong 

 to the deep-sea genera, Leptocyathus, Stephanophyllia, 

 Odontocyathus, Flabellum, &c. The Gasteropod and 

 Lamellibranchiate shells are, as I learn from Mr. E. Smith, 

 of shallow-water habit. This limestone contained 75 per 

 cent, of carbonate of lime, the residue being made up of 

 the common volcanic minerals, reddish siliceous casts of 

 Foraminifera, and fine washings. 



{b) A friable earthy rock, which, from the small size of 

 the minerals, the absence of bottom-living Foraminifera, 

 and the scarcity of pelagic forms, resembles a deep-sea 

 clay, and contains a thin coating of manganese between 

 the small layers or folds of the rock. This deposit, which 

 contains about 20 per cent, of carbonate of lime, occurs 

 in the upraised atoll of Santa Anna underneath the ele- 

 vated reef-mass. On the reef-flat in the vicinity of this 

 deposit there was observed by Lieut. Malan, as already 

 observed, a detached concretionary block of manganese 

 peroxides, one to two cubic feet in size : a typical fragment 

 that I brought home is, according to Mr. Murray, quite 

 similar to smaller masses dredged by the Challenger and 

 Blake. 



(c) A hard Foraminiferal limestone, chiefly composed 

 of pelagic I-'oraminifera. Of this rock, which was found 

 at the surface in Treasury Island, Mr. Murray observes 

 that the organisms, together with the minerals, are similar 

 to those found in deposits of modern seas near volcanic 

 islands at depths of from 500 to 800 fathoms. The Fora- 

 minifera are identical with those found in the surface- 

 waters of the tropics at the present day. 



With such data as the foregoing at my disposal, it might 

 appear an easy matter to gauge the amount of elevation 

 that has occurred in these regions in recent times. But 

 so great has been the sub-aerial denudation in these islands 

 that although the elevatory movements have brought up 

 to our view a deep-sea clay, with its concretion of man- 

 ganese, and a Foraminiferal limestone that was probably 

 formed in a depth of from 500 to 800 fathoms, two rocks 



* Vide Annals and Magazine of Natu7-al History, vol. xvi. p. 444. 



which occur in islands "at opposite extremities of the 

 group, yet, notwithstanding this great upheaval, the cal- 

 careous envelopes usually disappear from the slopes of the 

 volcanic islands at heights of 500 or 600 feet above the 

 sea, and never came under my observation in such islands 

 at greater elevations than 900 feet. The rainfall in the 

 elevated interior of the large islands cannot be much 

 under 300 inches in the year, since my own observations 

 place it at about 150 inches at the coast. Of the rapid 

 degradation of the surface which these calcareous districts 

 undergo during a heavy fall of rain, of as much as two to 

 three inches in the same number of hours, I was a fre- 

 quent witness. In a few minutes the whole hill-slope 

 discharges a continuous sheet of muddy water, the rivulets 

 swell to turbid streams, and the water rushes down the 

 permanent courses with the roar of a mountain torrent. 

 After the rain-storm has passed away, the band of muddy 

 water that fringes the whole length of the coast, to a 

 distance of one-quarter or one-third of a mile from the 

 shore, indicates the loss of material which the land-surface 

 has sustained. 



From the general character of these calcareous forma- 

 tions it may be safely inferred that they will be found 

 wherever there has been elevation during the recent period 

 in regions where coral reefs are flourishing. Amongst 

 other localities we may look to the West Indies, the Indian 

 Archipelago, New Guinea (more particularly the south- 

 coast). New Britain, New Ireland, the Santa Cruz Group, 

 the New Hebrides, the Loyalty Islands, New Caledonia, 

 and the Fiji and Tonga Groups, as likely to possess at the 

 sea-border formations of a similar character. In the 

 Solomon Islands, many other islands, such as Ulaua and 

 Ronongo, will be probably found to be counterparts of the 

 islands of Ugi and Treasury. 



Note. — A reference should be made to the occurrence 

 of worked flints of the pateolithic type in the soil of the 

 cultivated districts of these islands. The natives say they 

 have fallen from the sky, which reminds one of a similar 

 superstition prevalent in the country districts at home as 

 to the source of celts. I was never successful in finding 

 where they came from originally, and would recommend 

 future visitors to this group to pay attention to this point. 

 They are said to occur together with a chalk-like rock on 

 the beaches of Ulaua, an island which I was unable to 

 visit. (For further information on this subject, vide some 

 notes of my own read by Prof. Liversidge before the 

 Royal Society of New South Wales, Journal for 1883, 

 vol. xvii. p. 328.) 



TRACING A TYPHOON TO EUROPE 



AT the meeting of the Royal Meteorological Society 

 held on November 18, a paper by Mr. Henry 

 Harries, on " The Typhoon Origin of the Weather over 

 the British Isles during the second half of October, 1882," 

 was read. The author had prepared daily charts of the 

 North Pacific Ocean from September 26 to October 10, 

 and by permission of the Meteorological Council the 

 charts of the area between the western coast of America 

 and Eastern Europe were utilised. The earliest evidence 

 of the formation of the typhoon was on September 27, 

 some distance east-south-east of Manilla. At first the 

 movement was towards north-west, 5 miles an hour, 

 but on September 30, when the storm-area extended to 

 1300 miles north-west of the centre, it curved towards 

 north-east, crossed the south-eastern corner of Japan at 

 33 miles an hour, and attained a maximum rate of 51 miles 

 per hour on October 2 to 3, after leaving the Japanese coast. 

 In the neighbourhood of the Aleutian Archipelago the 

 progress was very slow until the 9th, when it rapidly 

 increased to 35 miles an hour, and entered Oregon on the 

 loth. The Rocky Mountains proved to be no obstacle to 

 the progress of the typhoon, which crossed the range at 

 36^ miles an hour, and, maintaining this rate, passed 



