Page:1902 Encyclopædia Britannica - Volume 26 - AUS-CHI.pdf/667

This page needs to be proofread.


CASPIAN SEA 611 1 according to the Aral-Caspian levelling). Its shores specially Caspian,, the following are known : one sponge {Metchnimostly belong to Russia, with the exception of the southern ■om«) the Cardides (Adacna and Hidacna), three Gastropods, coast, which belongs to Persia. Its general description and fom?,, VS1(1'S: two Amphipods, and the fish Clupeonella, while at eas om other genera belong, besides to the Caspian, only to such map were given in the ninth edition of this work. mums m meeks ot the Black Sea as have lost their salinity. As Hydrography. The hydrography of the Caspian was carefully to species which belong only to the Caspian fauna, we find them investigated in 1856-72 by Captain (afterwards Vice - Admiral) among the Protozoa, the Sponges (three), the Vermes (Oligoeheetes, Am llc ets Ivashintsefi, and by several later expeditions directed by 0. Grimm, Rj t ), the Molluscs (twenty-five species), numerous Andrusoti, I. Spindler, &c., whilst the subjects of its shores, its Amplupods and Mysids, the Fishes (species of Gobius, Benthophilus, former extension, and its geological history have been studied by Lobitis, &c.), and even the Mammals {Phoca caspia). It has been Russian geologists. Its basin is naturally divided into three por- shown, moreover, that most of those specifically Caspian species have tions. Of these the northern, extending from west to east, and had then ancestors m the Pontic fauna, and have diverged from the forming the great gulf Mortvyi Kultuk, is the shallowest, and ancestral type since the Caspian became isolated. The irruption hardly reaches a maximum depth of 20 fathoms. It is bein«- of the Mediterranean Sea into the Black Sea, in consequence of the gradually silted up by the deposits of the Volga, the Ural, and pieicmg of the Dardanelles, has destroyed many of the species the Terek. A depression, halt of which has a depth of more than w rich were retained in the Caspian, as well as in some lagoons oO fathoms, and reaches the maximum depth of 421 fathoms (detached fragments) ot the Black Sea. One representative of the occupies the middle portion of the sea. It may be considered as Caspian i&ma.(Glyptonolus entomon) does not appear either in the a contmuation of the synclinal depression of the Sea of Azov and B ack Sea or the Mediterranean, but belongs to the northern seas, Aorth Caucasia (Manych), and is separated from the southern and while several Caspian forms {Phoca caspia), some Mysicke {Ganideepest portion ot the Caspian by a submarine ridge, which is a marus, Amphicteis, &c.) have a northern character. This led to continuation of the main Caucasus range, and connects it with the the supposition, that the Caspian stood at some recent epoch in Kopet Dagh. ^ The depth of the Caspian over this ridge varies direct communication with the Arctic Sea. However, no traces iiom 30 to 150 fathoms.. Finally, the southern portion, which of such a connexion having as yet been discovered, the conjecture J lies at the foot of the high Elburz border-ridge of the Persian was abandoned. plateau, and which may be regarded as a continuation of the Kura The level of the Caspian is now taken at 86 feet below valley, has a depth of more than 500 fathoms in its middle (with that ot the ocean ; but it has undergone several oscillations in a maximum of 516 fathoms). modern times. Thus it appears from the researches of Filippoff Salinity. The salinity of the Caspian is but | of that of the that, during the years 1851 to 1888, it thrice stood at a maximum ocean, and m the surface layers it is only 0‘0075 in the northern —in 1885 m 1868-69 (highest level), and in 1882—while the portion and 0*015 in the middle. It is also smaller along the minima fell upon the years 1853 (lowest) and 1873—the total western coast than along the eastern, and the proportion of sul- range of these oscillations being 3 feet 6^ inches. Besides these phides is greater than it is in the ocean. changes, there are also the seasonal ones (lowest level in January Geology.—isolation of the Caspian from the ocean must highest m summer). The winds also show a certain periodicityJ have taken place, in the opinion of Russian geologists, at a rela- and they result in currents. ’ tively recent geological period. During the early Tertiary age it Climate. The northern portion of the Caspian which experibelonged to the great sea which covered all South Russia, and was ences severe frosts, and is too shallow to store in large amounts of in open communication with the ocean. Only during the Miocene heat m the summer, freezes for three or four months along the period, the so-called Sarmathian Sea of the geologists, which spread shores, but in the middle portion ice appears only when it is lrom the middle Danube. through Rumania, South Russia, and brought by northern winds. along both slopes of the main Caucasus ridge to the Caspian region Fisheries. —There is no other inland sea in the world so ricli began to be isolated , and partially to lose its salinity. Before the y? ^1S 1 ,?s ^asl^an the mouths of its great rivers, the beginning of the. Pliocene time it was broken into three separate U}® Und, the Terek, and the Kura. It was estimated, in parts, one of which was the Aral-Caspian basin. The deposits of orA2 aiT 1802, that every year no less than from 264,000 to that period are described as the Pontic, and their fossils point to 297,000 tons of various fish are caught in the North Caspian and a turther decrease of salinity. Towards the end of the Pliocene Mle Dr ion«10gives ^er .393,000 IfeAtons. ' Seal-hunting ^ Grimm’s ismore correct estimate for period, and undoubtedly so during the Post-Pliocene, the fauna of 1896 also an important item. that basin took the aspect which it has now in the Caspian. Its Navigation. Navigation on the Caspian is maintained by 213 remains, known as Aral-Caspian deposits, are widely spread round S and540 sailin , (39 per cent, S vessels, an aggregate of nearly the Caspian, which then stood at a level of about 100 feet above ?o“ 220,000 tons of therepresenting whole Russian commercial fleet) the present, according to Sjogren, but probably even more than V I 1 ai Sp0rt rery ear about 200 000 Q o oo ooA l f / > passengers and tiiat. During the Ice age the Caspian covered the Steppes which 3,200,000 tons of goods. The trade is partly with Persiaabout and now spread on its northern shore, probably joined the Black Sea partly coasting, immense quantities of naphtha and other produce (also isolated from the ocean), through the Manych depression, being exported from Caspian ports to Russia, while Russian goods and sent northwards a narrow gulf, up the present Volga valley as aie impoited to Caucasia and the Transcaspian territory for Turlar as the 56th degree of latitude (Aral-Caspian deposits are found on kestan and Bokhara. A considerable amount of goods, chiefly the lower Kuma). Eastwards it penetrated into the Transcaspian raw cotton, has been added to the traffic since the completion of territory between the Great and the Little Balkhan mountains, the Iranscaspian railway. The Caspian ports are entered every up the Uxboi which a few years ago was supposed to represent year by an average of 20,000 vessels (6000 at Astrakhan), mainly an old bed of the Amu-Daria, but which in reality is a dried-up ®ngaged m coasting trade. The chief Russian ports are: Astrakhan, strait ot the Aral-Caspian basin, the bottom of which is strewn Petrovsk, Derbent (recently improved), Baku, and Lenkoran on the with marine Post-Pliocene deposits. Joining what is now Lake west coast ; Krasnovodsk (head of Transcaspian railway) and Aral, it received both the Amu and the Syr. When the great ice- Mikhadovsk on the east coast; and Resht on Persian territory. oap, which covered two-thirds of European Russia, had thawed, A detachment of the Russian navy, consisting of seven gunboats 6 8 sef uell known as the “Caspian flotilla,” is kept on this sea. Its naval j. • l t general desiccation of the northern hemisphere (still continued) set in, the Caspian began to diminish, its level to station is at Ashur-ada, on an island close to the Persian coast. go down, while its connexions, both with the Black Sea and Lake The Gulf of Kaka-boghaz, or Kara-bugaz (also Aral, were broken. Faivna.—Tha fauna of the Caspian, well studied by Eichwald, Aji-daria or Kuli-daria), on the east coast of the Caspian owalewski, Grimm, Dybowski, Kessler, and Sars, gives support Sea, is a vast expanse of water which is separated from to the above views. It is a mixture of fresh-water and marine the Caspian by a narrow sand-bar pierced only by a terms ; thus we find in it the marine herring and such fishes narrow strait, about 1^ miles long and from 115 to 170 (Lyprinus, Perea, Silurus) as are, together with the fluviatile lobster, characteristic of fresh water. The Rhizopoda, Rotalia yards wide the Kara-bugaz strait. A current flows and lextillaria, one sponge {Amorphina), the Amphicteis worm, through it into the gulf at a rate of Ry to 37 miles per e mollusc Cardium edule, and various Cardidce, and some Amphi- hour. pods {Cumacea and Mysidce), are purely marine; but they are The area of this gulf being about 7500 square marine either such forms as easily support variations in salinity, or are especially characteristic of brackish waters. Of genera which are miles (100 English miles from W. to E. and 87 English miles from N”. to S.), its evaporation is very great. It 1 By the triangulation of 1840 its level was found to be 84 feet has been proposed to dam the strait in order to raise the eve i^ Sea.an The 860-70 gave 89* feet. ItBlack remains openCaucasus question triangulation whether such ofa level of the Caspian and to increase its salinity. The considerable difference can be explained by mere errors. But a longer suggestion has also been made that a wire net stretched series of observations of the changes of level due to accidental causes across the strait would prevent fishes from entering the (winds, rams) is required before any positive conclusions mavJ be gulf, where they get lost. Expeditions sent in 1895 made. and 1896 to study these questions discovered that the