April 15, 1SS0] 



NATURE 



577 



bracketed with that of Civet, «e must al.-o place there the lime- 

 stone of Frasne, as was done by Dumant. But M. Malaise 

 replies that Dumont's classification was founded on mere litho- 

 logical considerations, and that we can now trace palreontological 

 differences among these subdivisions. It is interesting to observe 

 among his fossils from the Upper Devonian] Psammites du 

 Condroz some of the forms which occur in the Br.rnstaple and 

 Marwood beds of Devonshire, with remains of fishes (Holopty- 

 chins nobilhsimns) of the Upper Old Red Sandstone of Scot- 

 land, and of ferns (PaLvoptcris Hibcmica) identical with those of 

 Kiltorcan in Ireland. 



Geology and Physical Geography of the Aralo- 

 . Basin. — The veteran geologist Count von Helmer en 

 lat year presented to the Imperial Academy of Sciences of St. 

 Peter-burg an interesting communication relative to the geologi- 

 cal changes which have taken place within tertiary and recent 

 times in the remarkable depression in South- Eastern and Asiatic 

 Russia. Considerable activity has for some years past pre- 

 vailed among Russian officials in regard to railway communi- 

 cation with the new acquisitions in that part of the empire. 

 In June, 1877, the Grand Duke Nicholas placed himself at 

 the head of an expedition which started from Orenburg with 

 the view of exploring the shortest railroad route to Tashkend — 

 the chief point in the central area of Russia in Asia. During 

 the progress of this expedition a sketch-geological map was 

 constructed and a collection of specimens was made which, 

 carefully labelled and accompanied with notes, were sent to 

 Count von Helmersen, whose life-long acquaintance with 

 Russian geology enables him to make the data thus supplied tell 

 a connected and interesting story. He points out that a much 

 larger area of Southern Russia and adjoining lands was 

 covered by the sea in Jurassic than in Cretaceous times ; that 

 the expan-e of salt water was further diminished in the Eocene 

 and Miocene, and still more in the Pliocene and Post-pliocene 

 periods, and that it is visibly decreasing now in the remnants of 

 it left in the Aralo-Caspian basin. That this should not be 

 regarded as a mere local phenomenon he thinks to be made 

 clear by well-known facts in Northern Russia and the surrounding 

 regions. In Siberia, for instance, the shells of molluscs still 

 living in the Arctic Sea are found southwards to a distance of 

 700 versts (nearly 500 English miles) from the northern coast, 

 and all round the Baltic recent marine shells are found up to 

 heights of sometimes 600 feet above the present sea-level. 

 Whether this retreat of the sea is to be explained by a general sub- 

 sidence of the ocean or an elevation of the land, or by both causes 

 combined is, he believes, a question which still awaits solution for 

 the wli le northern hemisphere, though it has been studied by so 

 many observers from the times of Limueus and Celsius down to 

 our own. After the floor of the Miocene sea had been in large 

 measure raised into land, the United Aralo-Caspian Sea must 

 have been connected with the Black Sea, and must have had the 

 form of a large arc, of which the vertex passed through the 

 country of the Turcomans and Khiva, and of which the eastern 

 limb stretched northwards beyond the present Aral Sea. It has 

 been commonly supposed that during some part of the later 

 Tertiary or Tost -Tertiary periods a connection existed between 

 this united Aralo-Ca-pian Sea and the Arctic Ocean. But the 

 Count holds that for this belief there is no proper foundation. At 

 the eastern base of the Ural Mountains, he asserts, there are in the 

 superficial deposits no vestiges of any livingspecies of marine shells . 

 The mollusca cited by Pallas and others from the plains of Western 

 Siberia are all referable to freshwater species. With regard to 

 the probable cause of the subsidence of the level of the Caspian, 

 Count von Helmersen believes that it is to be sought in the 

 gradual sinking of the ground. In the deeper southern half of the 

 Caspian, notably about Derbend and Baku such a sinking is 

 actually proved. Not there only, but over the area of the sea 

 itself, as far as the island Tscheleken, on the eastern shore, an 

 enormous quantity of carburetted hydrogen escapes from the 

 ground, and has perhaps been doing so for thousands of years. 

 The area over which this takes place loses in substance, the 

 ground gets looser, and is unable to withstand the great 

 pressure of the water of a deep sea and of the superincumbent 

 rocks. It is consequently pressed together, and sudden in- 

 falls sometimes occur. The wide extent of the area which sup- 

 plies the gas and naphtha emanations of the Caspian may be 

 understood from the statement that even as far north as Astra- 

 khan carburetted hydrogen gas instead of water has come up in 

 Artesian borings. But besides this subterranean cause of dimi- 

 nution the Count is of opinion that the facts indicate an absolute 



decrease in the waters of Central Asia. Though the dwindling 

 down of the Miocene and Post-miocene seas gives no certain 

 proof of such a decrease, yet the desiccation of the rivers of the 

 Steppes and the drying up of the lakes point to a change of this 

 nature. The author instances the rivers Sarafscham, Emba, and 

 Irgis, and all the streams descending from the north towards the 

 Lake Balka-h. This lake is fed only from the mountainous 

 country lying to the south. Everywhere all over the vast 

 Steppes and across into Persia and Afghanistan ancient wide lakes 

 are now represented by greatly diminished sheets of water, which 

 the rivers in many cases are unable to reach, as their currents are 

 gradually lost in the wastes. An interesting practical question is 

 connected with these discussions. Is it possible to form a con- 

 tinuous water-way from St. Petersburg, by the Volga, Caspian, 

 and Oxus, to Khiva or the borders of Bokhara? Could the 

 ancient channel of the Usboi again be filled with water so as to 

 afford a route from the Caspian eastward ? This matter is being 

 investigated by an expedition sent out for the 'purpose. Count 

 von Helmersen, however, believes that the desiccation of the 

 Usboi is only part of the vast continental diminution of rainfall 

 and water-supply, and that the artificial restoration of that channel 

 is impossible. Still it is difficult sometimes to define what is 

 impossible to modern engineering skill. 



GEOGRAPHICAL NOTES 



As an example worthy of being followed by our own and other 

 geographical societies, we call attention to the " Memorie della 

 Societa Geografica Italiana," vol. ii., parte prima (Rome, 18S0), 

 which is the first part of a volume intended to be dedicated 

 entirely to the zoological results of the Italian expedition to 

 equatorial Africa, under the command of the Marquis Antinori, 

 whose portrait serves for frontispiece. It is prefaced by a com- 

 munication from the Secretary of the Society (Sig. G. della 

 Vedova), giving an itinerary of the expedition, and in connection 

 with this there is a very excellent map showing the route. As is 

 well know n, the expedition principally explored the kingdom of 

 Schoa, immediately south of Abyssinia — a district of which we have 

 heard a good deal lately in connection w ith Egyptian politics, 

 and of which we shall no doubt hear a good deal more. We 

 have here an enumeration of the lepidopterous insects of the 

 expedition, drawn up by M. Charles Oberthiir, of Rennes, illus- 

 trated by a folded plate, apparently carefully executed after the 

 manner of lepidopterists, on which eight presumably new species 

 are represented. The list of known species shows but little of 

 the palxarctic element ; this has already become dissipated, and 

 we enter upon African ground as such ; but the species captured 

 were conspicuous, and include several of extremely wide distri- 

 bution. A note explains that this part is not absolutely original, 

 and that it also appears in the "Annali del Museo Civico di 

 Storia Naturale di Genova," vol. xv., and the introduction indi- 

 cates that the whole of this zoological volume will receive atten- 

 tion from the naturalists on the staff of, or in connection with, 

 the now renowned Genoa Museum. 



At the meeting of the Geographical Society on Monday evening 

 the Rev. Chauncy Maples, of the Universities' Mission, read a 

 paper on Masasi and the Rovuma district of East Africa. 

 Masasi appears to be the name of a district rather than of a tow n, 

 lying in about 11° S. lat. and 38 E. long., and some 120 miles 

 south-west from Lindi on the coast ; it consists of four mountains 

 lying east and west, and rising out of a dense forest. The station 

 of the Universities' Mission, which was formed in 1876, is situated 

 at the western extremity of the region, and to their west again a 

 vast forest stretches away towards Lake Nyassa. In describing 

 the nature of the route to Masasi, Mr. Maples took occasion to 

 remark that if a road should ever be constructed to connect Lindi 

 with Lake Nyassa, it would have to pass along the valley of the 

 Ukeredi, which presents no engineering difficulties. A note- 

 worthy feature of the Masasi district is its great fertility ; the 

 cassava attains an enormous size, and the rice, &c„ grown are 

 famous for miles round. The water is strongly charged with 

 iron, and salt is obtained in large quantities from the moi-t 

 ground under the hills. Ironstone is common, and extensively 

 worked. The missionaries have introduced several kinds of fruit, 

 and intend to try wheat. Mr. Maples afterwards described a 

 journey which he made in November, 1S77, to the valley of the 

 Rovuma River and the Makonde country. Throughout his paper 

 he furnished many interesting particulars respecting the tribes 

 inhabiting the country between the coast and Lake Nyassa. 



