Page:Science vol. 5.djvu/299

 Apkii. S, 1883.1

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��nearlj horlioiilal strain) of [lie Brazilisn plalemi are those of the Parntia, AniaKotiaa, Sao Fmnctico, unci Pitnialiyba baaina. That of the Parana hasiii, which may be considered as embracing the Uruguay, intiudes a iarge portion of the jirovinces ol Rio Grande  Siil, Santa Cntharins, Pamni!, and SHo Paulo; a smail part of south-neeCeru Miniu Geraes and soutbern Goyaz; and Ihe elevated portion of the province of Matto Grosso, and of the repiiblic of FaragLiay, lyhig between the Parana and Paraguay. The maximum elevation along the eastern bordi^r in the provinces ot Parani and Siio Paulo is approxi- mately 1,000 metres, tUc general level becoming a few hundred metres lower to the southward and westward, as the result not only of denudation, but also of a general lowering of the surface.

The Amazonian tablelniid includes the greater part of the provinces of Matto Grosso and Goyaz, a large part of southern Panl, and relatively small portions of soutli-easlem Amazonas and western Maranbao. It Is drained by the Tocan tins- Araguaya, Xingii, Tapajds, and lower Madeira, with its tribu- tary the Guapor^, all of which descend from the tableland iti a series of rapida, at a distance of from 100 to 200 miles from the Amazonas. The louthern mai^ln of this great tableland — an escarpment ris- ing to betwecTi 800 and 1,000 metres above the level of the sea. and facing the depression of tlio Paraguay and Guaporg — has received the name of Serra dos

The Sao Francisco tableland lies mainly to the west of Ihat river, in the western part of the prov- inces of Minas Geraes and Bahia, and rises to the height of about 800 metres. It is doubtful whether or not it extends over the watershed, so as to be coii- tinuous with those of the Tocantins and Pamahyba volleys. The latter occupies all, or nearly all, of the province of Piauhy, and a portion of soulheni Mar- anhlUi and western Cearii, and is perhaps continuous with the Amazonian tableland along the Tocantins divide.

All of these tablelands ore dee|>Iy cut by numer- ous river-valleys so as to present almost everywhere a mountainous aspect; and the ridgea formed by denudation are generally spoken of as mountains, and are represented as such on all maps of the em- pire.

The Brazilian portion of the Guiana plateau Is very Imperfectly known. Along the watershed be- tween the Amazonas and the rivers flowing lo the Caribbean Sea there are monntaius whose culminat- ing poinW are said to rise lo the elevation of 3,000 metres or more; and spurs of high lands extend to within a few miles of the Amaxonns at several points between the month of the Rio Negro and the sea. This region is drained by ilie Rio Negro, with its tributary the Hio Branco, and a number of smaller rivers, amonft which the JanmniW, Trombetas, Pard, Jary. and Araguary are the most Important.

The great Amazonian depression Is relatively nar- row along the lower river, below the mouth of the Rio Negro, the average width being probably between 100 and SOO miles. Above the Rio Negro and Madeira,

��in the province of Amaznnus, it widens conttiderably, so that it presents a bottle or flask shape. The river is generally bordered by low alluvial plains, often of considemble width, which are subject to overflow, and are full of lakes and anastomosing liile-ebannels of the great river, or of the lower courses of Its tribu- taries. The higher lands are either tablelands less than 300 metres In height, formed by deposits pe- culiar to the depression, or denuded outhers of the mai^ins of th: great continental plateaus an either side, or of the Andean plateau at the head of the

The Brazilian part of the Paraguay depression is the upper portion of the immense plains ot the basin of that river, which form a large part of the Argentine Republic, Paraguay, and easieni Bolivia. These plains lie several hundred raetrei lower than the lands of the platean that encircle tbem, and of Its numerous spurs and outhers. They are. for the mobt part, but slightly elevated above the level of the rivers (Ihe upper Paraguay and its tributaries) that [ravene them, and, during the wet season, be- come traiisformed into immense lakes and marshes.

The Atlantic border-region consists of a zone, gen- erally only a few miles In width, lying between the coast and the margin of the continental plateau. South of Rlode Janeiro It is constituted by low sand- plains full of lagoons, and by denuded spurs and outhers of the plateau. North of Rio de Janeiro there arc in many places. In addition to these, hills and tablelands of formations peculiar to tliis const- belt, which rite to a height of from 100 to 200 metres. O. A, Dkhbv.

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���AccoRDiNo to a late report by Lieut. -Commander Z. L. Tanner, U.S.N., commanding the U.S. Bsh- eoinmlssion steamer Albatross, dated at New Orieans, Feb. 13, the recent short cruise ot that vessel has been productive of some interesting n

The Albatross left Washington on the afternoon of the day before Christmas (1884), and after delay by Ice In the river, and by rough weather in Chesapeake Bay, arrived at Norfolk on the morning of the 26th. Having taken in coal at Norfolk, and received the parly of naturalists detailed for Ibe cruise,' she put to sea on the afternoon of Jan. 3 (1885), bound for Key West. At stariing, the very unusually high barometer of 31.10 was noted; but the glass began falling early next morning, with tl)D setting-in of a smart soulh-ensi gale and heavy sea. On the 6th, the weather having moderated, r line was set for tlle-Hsb, in 111 fathoms oft the Car- olina coast, but without result. Four hauls with the beam-trawl, with wlng-nels and mud-bags, in about the same locality, were more productive, bring- ing up many familiar species, and some new to the ship.

' Mi. J. K. Btn. T>r)^lod H. lleui, anJ Mr. Tliornu

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