made in nearly every province in the Brazilian Empire and the Republics of the River Plate, that true Carboniferous rocks will ever be found north of the province of Santa Catherina, unless it be in the adjoining one of Parana (lat. 25° S.) The province of Rio Grande do Sul contains three distinct Coalbasins, all of which I have examined, and ascertained, in some degree, the extent and thickness of the Coal-strata. They are all contained within the limits of lat. 30° and 32o S., long. 51° and 54° N., and are separated from each other by rolling hills of granite, syenite, mica-schist, and trachytic and basaltic rocks. The largest of these deposits is, perhaps, the one occupying the valleys of the rivers. Jaguarão and Candiota between lat. 31° and 32°, long. 53° and 54o. The sedimentary rocks forming this basin have an uniform inclination of 10° to 15° towards the south, and apparently rest upon the mica-schist and sienitic rocks which enclose the valley of the river Jaguarão and its confluents. The falling away of one side of a hill in this basin, near its basset-edge, on the banks of the Candiota, laid bare the strata to a considerable depth, disclosing five distinct beds of bituminous coal ranging in thickness from 9 feet to 25 feet, giving 65 feet as the total thickness of the coal exposed. The accompanying Section will show the order of superposition and thickness of the different beds as they appear on the face of the escarpment. The Sandstone (No. 1) is evidently the uppermost rock, and forms two ranges of hills, one dividing the waters of the Jaguarão from those of the Candiota, and the other separating the tributaries of the Candiota from those of the Jaguarão-chico. The thickness of this bed varies considerably, being in some parts completely worn away, and in others attaining a depth of upwards of 200 feet. It contains nodules of argillaceous peroxide of iron. Immediately below this sandstone is found the first seam of coal-shale, 9 feet thick, which can be traced wherever the superincumbent sandstone has been denuded, for about 50 miles along a line running N.E.-S.W., and for about 30 from N.W.-S.E. Below this is a bed of sandy-shale, three feet in thickness, containing ochreous oxide of iron in the form of septaria; this overlies a bed of semi-bituminous coal (No. 4) which rests upon a thin seam of whitish clay, below which is another bed of coal, separated by a thin bed of blue clay (No. 7) from coal of a highly bituminous nature and possessing a thickness of 17 feet; this again is divided by a parting of clay similar to No. 7, from a bed of coal containing bands of Cannel-coal, having a thickness of 25 feet and very bituminous. Impressions of paleozoic plants occur in this bed and in the ironstone shale (No. 11) upon which it rests. The thickness of this ironstone I have not been able to ascertain; but it evidently rests upon sandstone (No. 12), which is similar in every respect to the upper bed of sandstone. This is the lowest bed shown in the escarpment; but from observations which I took in another part I found that this sandstone (No. 12) rested upon beds of limestone, which in some places appear to be separated by mica-schist. The Carboniferous rocks of this basin have apparently been but little disturbed by eruptive rocks, although basaltic dykes of considerable width are evident in the surrounding schistose and syenitic hills. The second basin lies in the valley of the São Sepé, one of the tributaries of the river Jacuahy, in about lat. 30° 20′, long. 53° 30'. Two distinct beds of coal, one of 7 feet and the other of 14 feet thick, appear in this locality underlying the same sandstone beds, which in some places have been tilted up and overflowed by trachytic dykes. The Carboniferous deposits in this valley have been traced over an area of about 15 miles. son. The third coal-basin is near the town of the Sao Jeronymo, on the banks of the river Jacuahy, lat. 30°, long. 51° 30′. The coal in this place is being worked by a Lancashire coal-viewer, Mr. James JohnThe sections of two shafts sunk on the edge of the basin shew a superposition of rocks similar to the deposits on the Candiota. At the depth of 19 yards, a bed of highly bituminous coal 6 feet thick was met with; below this is a bed of iron-stone shale containing fossils of the same genera as those found in the beds at Candiota. The shafts have been carried on to a depth of 61 yards, passing through beds of coal varying in thickness from 2 feet to 6 feet, interstratified with blue clay and ironstone. The Carboniferous deposits in the province of Santa Catherina are situated in the southern extremity in lat. 2810, long. 48° 14′ to 48° 44. About 45 miles N.W. of the sea-port of Lagana the basin is intersected by the river Tubarão and its tributaries. By driving levels and sinking pits, five beds of coal of a thickness varying from one and a half feet to ten feet, have been met with, underlying a sandstone formation. An analysis of specimens from these beds, made by Professor Thomas Richardson, gave the following results: The specimens were taken from near the outcrop. In the Republic of Banda Oriental or Uruguay Carboniferous beds similar to the above, and underlying sandstone of the same character as that found above the coal-beds I have described, can be traced for many miles on the head waters of the Rio Negro, between lat. 31° and 320, long. 54° and 55°. Here the sedimentary rocks have undergone considerable displacement from the eruption of the trachytic rocks which characterize the surrounding country. South of this district, as far as the river Plate, no sedimentary rocks occur, except along the banks of the river Uruguay, where limestones are found. In Paraguay, on the head waters of the Tibicuari, I observed the same Sandstone formation, with beds of coal-shale, as that seen in Rio Grande do Sul and S. Catherina. |