April 3, 1885.] 



SCIENCE 



275 



nearly horizontal strata) of the Brazilian plateau 

 are those of the Parana, Amazonas, Sao Francisco, 

 and Parnahyba basins. That of the Parana basin, 

 which may be considered as embracing the Uruguay, 

 includes a large portion of the provinces of Rio 

 Grande do Sul, Santa Catharina, Parana, and Sao 

 Paulo; a small part of south-western Minas Geraes 

 and southern Goyaz; and the elevated portion of the 

 province of Matto Grosso, and of the republic of 

 Paraguay, lying between the Parana and Paraguay. 

 The maximum elevation along the eastern border in 

 the provinces of Parana and Sao Paulo is approxi- 

 mately 1,000 metres, the 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 tableland includes the greater- 

 part of the provinces of Matto Grosso and Goyaz, a 

 large part of southern Para, and relatively small 

 portions of south-eastern Amazonas and_ western 

 Maranhao. It is drained by the Tocantins-Araguaya, 

 Xingii, Tapajos, and lower Madeira, with its tribu- 

 tary the Guapore, all of which descend from the 

 tableland in a series of rapids, at a distance of from 

 100 to 200 miles from the Amazonas. The southern 

 margin of this great tableland — an escarpment ris- 

 ing to between 800 and 1,000 metres abov.e the level 

 of the sea, and facing the depression of the Paraguay 

 and Guapore — has received the name of Serra dos 

 Parecis. 



The Sao Francisco tableland lies mainly to the 

 west of that 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 con- 

 tinuous with those of the Tocantins and Parnahyba 

 valleys. The latter occupies all, or nearly all, of the 

 province of Piauhy, and a portion of southern Mar- 

 anhao and western Ceara, and is perhaps continuous 

 with the Amazonian tableland along the Tocantins 

 divide. 



All of these tablelands are deeply cut by numer- 

 ous river-valleys so as to present almost everywhere 

 a mountainous aspect; and the ridges 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 to the 

 Caribbean Sea there are mountains whose culminat- 

 ing points are said to rise to the elevation of 2,000 

 metres or more; and spurs of high lands extend to 

 within a few miles of the Amazonas at several points 

 between the mouth of the Rio Negro and the sea. 

 This region is drained by the Rio Negro, with its 

 tributary the Rio Branco, and a number of smaller 

 rivers, among which the Jamunda, Trombetas, Parii, 

 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 200 miles. Above the Rio Negro and Madeira, 



in the province of Amazonas, it widens considerably, 

 so that* it presents a bottle or flask shape. The river 

 is generally bordered by low alluvial plains, often of 

 considerable width, which are subject to overflow, 

 and are full of lakes and anastomosing side-channels 

 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 outliers of the 

 margins of the great continental plateaus on either 

 side, or of the Andean plateau at the head of the 

 basin. 



The Brazilian part of the Paraguay depression 

 is the upper portion of the immense plains of the 

 basin of that river, which form a large part of the 

 Argentine Republic, Paraguay, and eastern Bolivia. 

 These plains lie several hundred metres lower than 

 the lands of the plateau that encircle them, and of 

 its numerous spurs and outliers. They are, for the 

 most part, but slightly elevated above the level of 

 the rivers (the upper Paraguay and its tributaries) 

 that traverse them, and, during the wet season, be- 

 come transformed 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 Rio de Janeiro it is constituted by low sand- 

 plains full of lagoons, and by denuded spurs and 

 outliers of the plateau. North of Rio de Janeiro 

 there are in many places, in addition to these, hills 

 and tablelands of formations peculiar to this coast- 

 belt, which rise to a height of from 100 to 200 metres. 



O. A. Derby. 



THE LAST CRUISE OF THE ALBATROSS 

 IN THE GULF OF MEXICO. 



According to a late report by Lieut. -Commander 

 Z. L. Tanner, U.S.N., commanding the U. S. fish- 

 commission steamer Albatross, dated at New Orleans, 

 Feb. 13, the recent short cruise of that vessel has 

 been productive of some interesting results. 



The Albatross left Washington on the afternoon 

 of the day before Christmas (1884), and after some 

 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 party of naturalists detailed for the 

 cruise, 1 she put to sea on the afternoon of Jan. 3 

 (1885), bound for Key West. At starting, the very 

 unusually high barometer of 31.10 was noted; but 

 the glass began falling early next morning, with the 

 setting-in of a smart south-east gale and heavy sea. 

 On the 6th, the weather having moderated, a trawl- 

 line was set for tile-fish, in 79 fathoms, off the Car- 

 olina coast, but without result. Four hauls with 

 the beam-trawl, with wing-nets and mud-bags, in 

 about the same locality, were more productive, bring- 

 ing up many familiar species, and some new to the 

 ship. 



i Mr. J. E. Benedict (in charge), Capt. J. W. Collins, Dr. 

 Tarleton H. Bean, and Mr. Thomas Lee. 



