Matto Grosso is one of the regions of least roughness on the continent of South America. There are no elevations of the land which constitute real mountains. The elevated lands have their points of culmination in the western bases of the Mantiqueira, the Aymorés, and the Espinhaço, and continue, gradually lowering from this side to the West of Goyaz, and on the other side are the elevated lands at the base of the Andes, which incline to the East with its supports. Elysée Reclus says that an intermediary plain, separating the two geographical districts, goes winding in the form of a valley, that in other ages certainly was a maritime strait separating the two islands—Western Brazil and the Andes. To-day rivers run in the depression where formerly there was a sea and the plain is actually full of alluvial soil. The true center of South America is between the two cities of Cuyabá and Corumbá. To those who do not know the region, the slopes of the hills are mistaken for mountains and geographical maps show a chain of mountains more or less continuous, between the basins of the Tapajóz and the Madeira, between the head waters of the same Tapajóz and Paraguay and finally between the Tapajóz and the Araguaya. Nevertheless this semi-circular plain exists only in fragments, because the elevations which are found in the plains of the upper Paraguay and its tributaries are only a high, level ground of horizontal sections or slight elevations and worn away by the rivers which flow into the great Amazon. [Illustration: REMOVING THE BALL OF RUBBER AFTER IT HAS BEEN SMOKED.] They are rather tablelands than mountains, for they do not reach an elevation, except in some parts of the tableland, of more than 100 meters, while the mean elevation of a range of mountains is 500 meters.