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Capodistrias, who confiscated their holdings in Greecej, returned two members to the Irish parliament. The and more recently they have been stripped of their principal trade is in corn, which is ground at the neigh. possessions in the Danubian principalities. They still bouring mills. Population in 1871, 4510. retain some property in parts of the Archipelago. A ATINA, a town of Naples, province of Terra di Lavoro, Turkish official resides at Caryes, and collects the taxes, near the Melfa, and 12 miles S. E. of Sora. It has a which amount to about ten shillings a head; but for the cathedral, convent, and hospital, with about 5000 inhabimost part the peninsula is autonomous, being governed by tants; but it is cbiety remarkable for its ancient remains, an administrative body of four presidents (CALOTÁTau), one consisting of portions of its walls, the ruins of an extensive of whom bears the title of “First Man of Athos," and a aqueduct, and numerous other structures, besides monurepresentative body called the Holy Synod, which consiste ments and inscriptions. The city is of great antiquity, of twenty members, one from each of the monasteries and was a place of importance down to the days of the proper. These twenty communities are partly Cænobitic, Roman empire. It is remarkable now, as of old, for the with a common stock and a warden, and partly Idiorrhyth- exceptional coolness of its situation. mic, with a kind of republican government and great ATITLAN, a lake in the department of Solola, in individual liberty. Besides these regular monasteries, Guatemala, 20 miles long, with an average breadth of 9 there are a number of dokytúpla, or sketes, which consist of miles. It seems to occupy the crater of an extinct volcano, several small associations gathered round a central church and its depth is reported to be very great. The scenery in and numerous little communities known as kaliouata, or the neighbourhood is striking and picturesque, the volcano retreats, as well as genuine hermitages. Harmony is not of Atitlan rearing its head 12,500 feet above the level of always maintained between the different establishments, as the sea. A little Indian town, Santiago de Atitlan, nestles was shown by a bitter dispute about a water-course between at the foot of the mountain. Cutlumusi and Pantocratoros, which led to the interference ATLANTA, the capital of Georgia, one of the United of the British consuls of Salonica and Cavalla, in answer States of North America, is situated about 7 miles to the to an appeal from some Ionian monks who were British S.E. of the Chattahoochee River, at an elevation of 1100 subjects (1853). For the most part, however, the inhabi- feet above the sea. Laid out in 1845, and incorporated as tants of Athos are quiet and moderately industrious. They a city in 1847, it has since rapidly increased. It is the are said to number about 3000, all men ; for no female, centre of a large trade in grain and cotton, and has even of the lower animals, is permitted to desecrate the pre extensive railway communication in all directions. Encincts of the Holy Mountain.

gineering work of various kinds is carried on, as well as the "Descriptio Montis Atho et xxii. ejus Monast.,” by Jo. Comnenus in

manufacture of cast-iron, flour, and tobacco. There are Montfaucon's Palæographia Græca; Georgirenes, Description of Pre. | two national and two savings banks. Educational institument State of Samos, Patmos, Nicaria, and Mount Athos, Lond. 1678; tions are numerous, and comprise the North Georgia Lient. Webber Smith, “On Mount Athos," &c, in Jour. Roy. | Female College, Oglethorpe College, a medical college, a uniGeog. Soc., 1837 ; Curzon, Visits to Monasterics in the Levant, 1849; Fallmerayer, Fragmenta aus dem Orient, 1815 ; Gass, Commen:

versity for men of colour, and a variety of schools. The latio Historiea, &., and Zur Geschichte, &c., 1866; Ramner's Hist. / state library contains upwards of 16,000 volumes. Thero Taschenbuch, 1860 (art. by Pischon); Report by M. Minoidenre about thirty churches of different denominations, the Minas, 1846 ; J. Müller, Denkmäler in den Klöstern von Athos; Methodists being most largely represented, and one of their Langlois, Athos, &c.; Didron's Iconographie Chrétienne, 1844 : Journal Asiatique, 1867; Tozer's Highlands of Turkey, 1869.

churches ranking among the finest buildings in the city.

During the war Atlanta was the centre of important ATHY, a market-town of Ireland, county of Kildare, military operations, and suffered greatly in consequence 34 miles S.W. of Dublin. It is a station on the Great (1864). It was strongly fortified by the Confederates, and Southern and Western Railway, and is intersected by the defended, first by General Joseph E. Johnston, and then river Barrow, which is here crossed by a bridge of five by General Hood, against the attack of General Sherman. arches. It has a church, a Roman Catholic chapel, a Hood was compelled to evacuate the city, and Sherman Presbyterian and a Methodist meeting-house, court-house, afterwards retired to Chattanooga,-movements which jail, two banks, hospital, dispensary, barracks, &c. Adjoin- occasioned the destruction by fire of the greater part of the ing the town is a small chapel, an ancient cemetery, and a buildings, both public and private. Population (1860), small Dominican monastery. Previous to the Union it | 9554; (1870), 21,789.

ATLANTIC OCEAN

M HE designation Atlantic Ocean, originally given to the circle. The line which separates its southern extension

T sea that lies beyond the great range of Atlas in from the Indian Ocean may be considered to be the North-western Africa, has come to be applied, with the meridian of Cape Agulhas, the southernmost point of the extension of geographical knowledge, to the whole of that. African continent; whilst the boundary between the South vast ocean which occupies the wide and deep trough that Atlantic and South Pacific would be formed in like manner separates the New from the Old World. Its limits are by the meridian of Cape Horn. Although the Baltic and variously defined; some geographers regarding it as the Mediterranean are commonly regarded as appendages extending from pole to pole, whilst others consider it as to the Atlantic, yet their physical conditions are so peculiar bounded at its northern and southern extremities by the as to require separate treatment. (See BALTIC and MEDIArctic and Antarctic circles respectively. As the peculiarity TERRANEAN.) of the physical conditions of the Polar Seas renders it on Every physical geographer who has written upon the every acoount more appropriate to describe them under a Atlantic has noticed the curious parallelism between its separate head (POLAR Regions), the Atlantic will be here eastern and its western borders,--their salient and retiring treated as bounded at the north by the Arctic circle, which angles corresponding very closely to each other. Thus, nearly corresponds with the natural closing-in of its basin beginning at the north we see that the projection formed by be the approach of the coasts of Norway and Greenland | the British Islands (which extends much further westwards with Iceland lying between them; while at the south, where at 100 fathoms below the surface than it does above the the basin is at its widest, its only boundary is the Antarctic sea-level), answers to the wide entrance to Baftiu's Pay: whilst, on the other hand, the projection of the American as equally inapplicable to any other valley of similar width coast at Newfoundland answers to the Bay of Biscay. and depth. Further south, the great rounded prominence of Northern The general direction of geological opinion, indeed, has Africa corresponds with the vast bay that stretches from of late been, on physical grounds, towards the high antiNova Scotia to St Thomas; whilst the angular projection quity of the great oceanic basins, not exactly as at present of South America towards the east corresponds with that bounded, but as areas of depression having the same rela. receding portion of the mid-African coast-line which is tion as they have now to the areas of elevation which form known as the Gulf of Guinea.

the great continents. Thus Sir Charles Lyell was strongly This correspondence suggested to Humboldt the idea that impressed by the fact that the mean depth of the sea is the Atlantic basin was originally excavated by a very not improbably fifteen times as great as the mean height violent rush of water from the south, which, being repulsed of the land ; and that depressions of the sea-bottom to a by the mountain ranges of Brazil, was directed by them depth of three miles or more extend over wide areas, whilst towards the coast of Africa, and formed the Gulf of elevations of the land to similar height are confined to a Guinea; being there checked and turned to the west by few peaks and narrow ridges. Hence, he remarked, “while the mountains of Upper Guinea, the stream excavated the the effect of vertical movements equalling 1000 feet in Caribbean Sea and the Gulf of Mexico; and issuing | both directions, upward and downward, is to cause a vast thence, it ran between the mountains of North America | transposition of land and sea in those areas which are now and Western Europe, until it gradually diminished in continental, and adjoining to which there is much sea not velocity and force, and at length subsided. Another writer exceeding 1000 feet in depth, movements of equal amount speaks of the basin of the Atlantic as an immense rift, made would have no tendency to produce a sensible alteration by some terrible force, which rent the surface-land asunder, in the Atlantic or Pacific Oceans, or to cause the oceanic but left the edges of the ravine to show by their form that and continental areas to change places. Depressions of they had once been connected. For neither of these specula- | 1000 feet would submerge large areas of the existing land; tions, however, is there the smallest foundation in fact. What but fifteen times as much movement would be required to has to be accounted for, indeed, in regard to either of the convert such land into an ocean of average depth, or to great areas at present covered by water, is not so much the cause an ocean three miles deep to replace any one of the excavation of its sea-bed, as its segregation from an ocean existing continents.”? And Professor Dana, who, more originally universal by the boundaries that now enclose it; than any other geologist, has studied the structure of the in other words, not so much the depression of the bottom existing continents and the succession of changes concerned of its basin as the elevation of its sides. Not only is the in their elevation, has been led, by the consideration of the proportion of the land-surface of the globe to its water probable direction of the forces by which that elevation was surface scarcely more than one-third (being as 1 to 2:78), effected, to conclude that the defining of the present conbut the entire mass of the land which thus corers little tinental and oceanic areas began with the commencement more than one-fourth of the surface of the globe is quite of the solidification of the earth's crust. “The continental insignificant in comparison with that of the water which areas are the areas of least contraction, and the oceanic covers the remaining three-fourths. For whilst the average basins those of the greatest, the former having earliest had elevation of the whole land is certainly less than one-fifth a solid crust. After the continental part was thus stiffened, of a mile, giving from 9 to 10 millions of cubic miles as and rendered comparatively unyielding, the oceanic part the total mass of laud that rises above the sea level, the went on cooling, solidifying, and contracting throughout; average depth of the sea (so far as at present known) may consequently, it became depressed, with the sides of the be taken at about 2 miles, giving a total of nearly 290 depression somewhat abrupt. The formation of the oceanic millions of cubic miles of water, which is therefore about basins and continental areas was thus due to unequal thirty times the mass of tho land. From the computation radial contraction.'” In the opinion of Professor Dana, of Keith Johnston, it appears that, “if we conceive an there has never been any essential change in the relations equalising line, which, passing around the globe, would of these great features. “ It is hardly possible,” he says, leave a mass of the earth's crust above it, just sufficient to "to conceive of any conditions of the contracting forces that fill up the hollow which would be left below it, this line should have allowed of the continents and oceans in after would then fall nearly a mile below the present level of time changing places, or of oceans, as deep nearly as existthe sea.” This is tantamount to saying that, if the solid | ing oceans, being made where are now the continental areas; crust of the earth could be conceived to be smoothed down although it is a necessary incident to the system of things to one uniform level, its entire surface would be covered that the continental plateaus should have varied greatly with water to the depth of about a mile. Hence it is in their outline and outer limits, and perhaps thousands of obvious that as the elevation of that crust into land over feet in the depths of some portions of the overlying seas, certain areas must be accompanied by a corresponding and also that the oceans should have varied in the extent depression of the sea-bed over other areas, such depression, of their lands." ... “The early defining, even in Archæan augmenting in those areas the previous depth of the aqueous times, of the final features of North America, and the concovering of the globe, would be quite sufficient to account formity to one system visibly marked out in every event for the existence of the great oceanic basins, without any through the whole history in the positions of its outlines excavating action. And a confirmation of this view is and the formations of its rocks, in the character of its found in the fact, ascertained by recent soundings, that the oscillations, and the courses of the mountains from time to deepest local depressiɔns of the sea-bed are met with in time raised-sustain the statement that the American conthe neighbourhood of islands that have been raised by tinent is a regular growth. The same facts also make it volcanic agency. Further, as the quantity of solid mat evident that the oceanic areas between which the continent ter that must have been removed (on Humboldt's hypo

The case of such a shallow trough as that of the English Channel, thesis) in the excavation of the Atlantic valley must

of the former continuity of whose sides there is ample evidence, whilst its bottom is nowhere 500 feet beneath the surface, is obviously alto

gether different. The extraordinary depth of the Mediterranean basin, sible to conceive of any mode in which such a mass can

on the other hand, affords strong reason for regarding it as, like the have been disposed of, wo may dismiss that hypothesis

Atlantic, & portion of the original area of depression, circumscribed by

the elevation of its borders. as not only untenable in regard to the Atlantic basin, but ? Principles of Geology, 11th ed. ml. i. p. 269

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ENCYCLOPEDIA BRITANNICA NINTH EDITION

lies have been chief among the regions of the earth's crust be regarded as representing the original sea-bed (from that have used the pent-up force in the contracting sphere which the Azores have been lifted up by volcanic action), to carry forward the continental developments. If this whilst the deep valleys on either side of it are “areas of was true of the North American continent, the same in subsidence" answering to the “ areas of elevation ” of the principle was law for all continents.”1

land that borders them. Dimensions of the Atlantic.—The length of the Atlantic Generally speaking, the depths of these valleys increase basin, considered as extending from the Arctic to the pretty rapidly with the distance from the shore-line, 80 Antarctic circle, is nearly 8000 geographical miles. The that the contour-lines of one and two miles follow the nearest approach of its boundaries is between Greenland shore-lines pretty closely. But there are two localities in and Norway, whose coasts are only about 800 miles apart. which shallow water extends to a much greater distance They thence recede from each other towards the south, from land than it appears to do elsewhere. One of these as far as the parallel of 30° N. lat., where, between the lies in the neighbourhood of the British Isles. For a dispeninsula of Florida and the western coast of Marocco, tance of about 230 miles to the westward of Ireland there there is an interval of 70° of longitude, or about 3600 is a slope of only about 6 feet in a mile ; but in the next geographical miles. The channel then rapidly narrows as 20 miles there is a fall of 9000 feet, after which there is it passes southward, so that between Cape St Roque in little change of level for 1200 miles. Hence as the depth Brazil (5° S. lat.) and the coast of Sierra Leone (between of the sea immediately surrounding the British Isles is 50 and 8° . lat.) the African and American continents nowhere 100 fathoms (so that an elevation of their whole approach within 1500 miles of each other. The sudden area to that amount would unite these islands not only to eastward recession of the African coast as it approaches the each other but also to the continent of Europe), it is equator, and the westward trend of the South American obvious that the platform on which they rest is really, coast-line between Cape St Roque and Cape Horn, widen although now submerged, a part of the land-mass of out the South Atlantic basin to the same breadth as that Europe. Another of these extensive shallows is that of of the North Atlantic in the parallel of 30° N.,—the which the Banks of Newfoundland form the highest part; interval between the Cape of Good Hope and the estuary and of the existence of this a probable explanation may of La Plata, in the parallel of 35° S., being no less than be found in the accumulation of the rock-masses that are 731° of longitude, or about 3600 geographical miles. brought down by icebergs every summer from the coasts

The depth of the North Atlantic has been more care of Greenland and Labrador. For it is now generally fully and systematically examined than that of any other admitted that these icebergs are really parts of glaciers, that oceanic basin ; and the general contours of its undulating were originally formed on the mountain-slopes of Greenland sea-bed may now be regarded as pretty well determined. and Labrador, and then descended valleys which open out Putting aside the older soundings as utterly untrust. on their coasts, so as, on arriving at the mouths of these worthy, and accepting only those taken by the modern valleys, to detach themselves and float away, being borne methods, whose reliability has been amply tested by the southwards by the Folar Current to be presently described. accordance of diversified experiences, we can now assert Most Arctic icebergs of which a near view can be obtained with confidence that scarcely any portion of its floor has are observed to have upon them a considerable number of a depth exceeding 3000 fathoms, or about 3.4 miles, the pieces of rock, sometimes of a very considerable size ; and greatest dopth determined by the recent “Challenger” sound-these are of course deposited on the sea-bed when the ings, which was that of a limited depression about a icebergs melt (which they usually do on the borders of the hundred miles to the north of St Thomas, having been Gulf Stream), thus forming a vast conglomerate bed, to 3875 fathoms, or about 4:4 miles. Except in the neigh- which parallels are not improbably to be found in various bourhood of its coast-lines, and in certain shallower areas geological epochs. to be presently specified, the floor of the basin at its Geological Age of the Atlantic Basin.-Guided by the widest part seems to lie at a depth of from 2000 to 3000 principle that great oceanic basins are to be considered fathoms, its slopes being extremely gradual. The central rather as original marine areas that have been limited by portion of the principal basin of the North Atlantic, the elevation of their boundaries, than as having been however, is occupied by & plateau of irregular shape, of formed by the excavation of terrestrial areas, we have to which a considerable part lies at a less depth than 2000 inquire what evidence there is that the basin of the Atlantic fathoms. Of this plateau the Azores may be regarded as has undergone any considerable change within a comparathe culmination; and that group being taken as its centre, tively recent period. it may be said to extend to the north as far as lat. 50°, and As has been pointed out by Prof. Wyville Thomson to the south-west as far as the tropic of Cancer. The (Depths of the Sea, p. 473), it is difficult to show that any nurthern extension of this plateau narrows out into a sort oscillations have occurred in the north of Europe since the of isthmus, which connects it with the plateau that occupies termination of the Secondary period, to a greater extent than a great part of the Atlantic basin to the north of 50° N. from 4000 to 5000 feet,—this being the extreme vertical lat. ; and it is across this isthmus, and along the bottom depth between the base of the Tertiaries and the highest of the deep narrow valley on either side of it, that the point at which Tertiary or post-Tertiary shells are found on telegraph cables are laid between Ireland and Newfound the slopes and ridges of mountains. Such oscillations, while land. Whether its south-western prolongation, known as the considerably modifying the boundaries of the Atlantic, would “Dolphin Rise" (fig. 1, infra) extends to the equator, so as not seriously affect the condition of the deeper parts of its to become continuous with the elevated area which cul- | sea-bed; and hence it may be concluded that the two deep minates in St Paul's rocks, and by a further southward ex valleys, one on the European side of the modern volcanic tension becomes continuous either with the volcanic elevation platform of the Azores, and the other on the American, of St Helena and Ascension Island, or with the elevation each having a width of 600 or 700 miles, and an average in the middle of the South Atlantic which culminates in depth of 15,000 feet, could neither have been formed by the island of Tristan da Cunha (fig. 2), has not yet been such oscillations, nor could, when once formed, have been ascertained. According to the view already suggested as converted into dry lang. It will be presently shown that to the formation of the Atlantic basin, the plateau might this idea of the existence of an Atlantic basin correspond1 "On some Results of the Earths Contraction from Cooling,” in

ing generally to that now existing, as far back as the later Amer. Journ. of Serence, June 1873. »

| Secondary period, is strongly supported by the evidence

IIJ.-23

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