Olenellus, a small trilobite, and typical of Lower Cambrian strata. Beneath this Serpulite grit lies a quartzite formation, and while the Torridon sandstone is found lying unconformably below the quartzite. Hence this Torridon sandstone, which Sir Roderick Murchison placed among the Cambrian strata, must be of pre-Cambrian Age. Traces of annelids and other organisms found in this group are thus the earliest remains of life in the British Isles of which we have any knowledge. Sedimentary strata of even earlier date than the Torridon sandstones appear to have been found by Mr. C. T. Clough, who has detected bands of graphitic schist lying evenly bedded in layers of an acid mica schist in the West of Ross-shire. An interesting observation has been made by Dr. E. O. Imhof in the course of an investigation into the fauna of the Scandinavian lakes. He finds that some of the deep water forms found in these lakes are either identical with or very similar to forms now existing in the North Sea or the Baltic, so that we have proofs that at a comparatively recent period many of these lakes must have been connected with these larger bodies of water.

Sir Robert Ball has pointed out an inaccuracy in Herschel's "Outlines of Astronomy" which has an important bearing on Croll's theory of the Ice Age. This inaccuracy has reference to the distribution of heat received on a hemisphere from the sun in one year. Sir Robert Ball points out that if 100 represents the total number of heat units received during a year, then sixtythree of these will be received during the summer and thirty-seven during the winter. As owing to the eccentricity of the earth's orbit the duration of either summer or winter varies from a maximum of 199 to a minimum of 166 days, the heat units received either in summer or winter may be crowded into the 166 or spread out over the 199. When the maximum length of summer occurs, a mild genial climate will be experienced, but when the maximum length of winter visits a hemisphere, that hemisphere will experience a long cold winter, producing a glacial condition which the short hot summer is unable to entirely overcome, and this condition, lasting as it would do for centuries, seems to be quite capable of producing all the phenomena of the Great Ice Age.

GEOGRAPHY.

Measurements of the parallel of latitude 52° N., reaching across Europe from Valencia to Orsk, in Siberia, have been in progress for many years. These measurements, although not yet quite completed, some gaps in the line being still unmeasured, yet have been carried sufficiently far to show that the length of the degrees of longitude along this parallel are not the same as would be the case if the section of the earth were a perfect circle. The earth is consequently an irregular spheroid, its surface, even after allowing for the hills, being a constantly varying curve. New determinations of the density of the earth have been made by M. Cornu, who has modified the apparatus of Cavendish so as to enable more accurate results to be obtained. The longitude of many places on the West Coast of Africa has been determined by Commander Pullen, who died at Bonny during the work in October 1890. Geographers have been supplied with a new lake in San Diego, county California, by an overflow from the Colorado river, which has covered several miles of a dry desert area previously almost destitute of water. Surveying work has been carried on during the past year with great energy in many parts of the world. Japan is being mapped on a scale of 1-20,000, and of this more than 300 sheets have been already published. The surveys, conducted

under the control of the Indian Government, have made good progress in Beloochistan, under Sir R. Sandeman, while Eastern and Northern Burmah have engaged the services of three parties under officers of the Royal Engineers. The survey of Siam is being carried out under the supervision of an Indian survey official, Mr. McCarthy, and the Shan States between Siam and Burmah are being explored by Lieutenant Ehlers. A large amount of survey work has been completed in the new British territories in Africa, while in North America the mapping of the continent is being rapidly carried forward by the three Governments interested. The Polar regions have received very little actual attention. Dr. Nanson's projected Antarctic expedition has been postponed, and the exploration of that vast unknown land is to be carried out by a joint arrangement between the Australian colonies, with the munificent help of Baron Dickson and Sir Thomas Elder, each of whom has contributed 5,000l. towards the total expense. In the Arctic regions Lieutenant Ryder has been heard of as late as July 26, when he was in latitude 72° 40′ N. on the East Coast of Greenland, and Mr. Peary landed at McCormick Bay in the same month for the purpose of visiting the northern parts of Greenland. In Australia another party is to be sent out under Mr. D. Lindsay, who has already had so much experience in exploration work, in order to clear up the geography of the unknown tracts between the central parts of Western and South Australia. In Eastern Asia Mr. A. R. Agassiz has completed an adventurous overland journey from the French territories of Tongking to Canton, and Mr. Pratt has visited the upper reaches of the Yang-tze-kiang. The lofty regions of Central Asia are gradually becoming opened up by the persistent efforts of travellers, and several noteworthy expeditions have been successfully carried out. Among them is a remarkable journey by M. J. Martin. Starting from Su-chow, a town near the Great Wall, on the Northwest corner of China, M. Martin passed north-westward by L. Alak across the Great Desert of Gobi to Karashir, in Eastern Turkestan. He then followed the river Tarim southwards to its mouth, and then made his way from Lob Nor, in a south-westerly direction, to Khotan, on the borderland between India and Turkestan. The Russian explorers have also not relaxed their efforts. The passes of Kafiristan are being explored by Captain Bachevski, who is taking up the work relinquished by Colonel Grombchevsky. In this district Russian and British officers have crossed and recrossed each others' tracks in a way which clearly foreshadows the time when the frontiers of these two Powers will meet. An expedition, under Colonel Yanof, actually arrested Captain Davison and took him to Ferghana, on the plea that he was in Russian territory; but this did not prevent Colonel Yanof on his part from trespassing with a military force of Cossacks into land distinctly within the British sphere of influence. Colonel Younghusband has given an account of his travels in the Little Pamir. He describes it as a desolate, cold, and barren region, quite incapable of supporting an armed force, and thus serves an additional confirmation, if such were needed, of Mr. Littledale's wanderings in the same inclement region. But the development of Russian influence in Central Asia has not sufficed to engross the whole of Russia's available energy. Two attempts have been made to gain a footing in Africa. One of these speedily collapsed, but a second, under the command of a Cossack named Mashkof, has started from Obok after a previous journey to the court of King Menelek in Abyssinia. Portugal appears to have fallen behind in the race; but German expeditions have been vigorously at work on both the East and West Coasts. German East Africa is being opened up by a nume

rous band of explorers, among whom are Rindermann, who is in charge of the meteorological and climatic observations; Hochstetter, who is surveying the Victoria Nyanza; Dr. Lieber, the geologist, and Vogler, a practical agriculturist. In spite of some mishaps, and one or two serious rebuffs in encounters with the natives, much sound exploratory work has been accomplished. On the West Coast Lieutenant Morgen left Kribi in the early summer of 1890, and made his way northwards to the river Benue. French explorers have been active in the region between Lake Tchad and the Congo, but have met with several serious mishaps, Crampel having been assassinated at El Kuti, and Captain Delporte having died on the Congo of fever. In the extreme East of Africa a large amount of entirely fresh country has been visited. The whole Somal territory from Magadoxo in the South to Berbera on the Gulf of Aden has been crossed by Briechetti, and two other explorers, Captain di Vesme and G. Candeo, have reached the upper waters of the Webi Shabeli, having started from Berbera and worked southwards. The opening up of Mashonaland has been the task to which British energy has been chiefly devoted, but with Mr. H. H. Johnston and Mr. Joseph Thomson at work, Northern Zambesia has not been neglected. In Ibea Mrs. French Sheldon made a journey to the foot of Kilimanjaro, and Captain J. R. L. Macdonald has been engaged in surveying the various routes leading from the Victoria Nyanza to the coast. So rapid has been the progress made in opening up South and East Africa, that a railway may soon be in steady operation through lands which only a few years ago were almost utterly unknown.

OBITUARY

EMINENT PERSONS DECEASED IN 1891.1

JANUARY.

T