BAHIA BLANCA TO BUENOS AYRES.

September 8th.—Having with some difficulty hired a Gaucho to accompany me, on my ride to Buenos Ayres, we started early in the morning. The distance is about four hundred miles, and nearly the whole way through an uninhabited country. Ascending a few hundred feet from the basin of green turf on which Bahia Blanca stands, we entered on a wide desolate plain. It consists of a crumbling argillaceo-calcareous rock, which, from the dry nature of the climate, supports only scattered tufts of withered grass, without a single bush or tree to break the monotonous uniformity. The weather was fine, but the atmosphere remarkably hazy; I thought the appearance foreboded a gale, but the Gauchos said it was owing to the plain, at some great distance in the interior, being on fire. After a long gallop, having changed horses twice, we reached the Rio Sauce. It is a deep, rapid, little stream, but not above twenty-five feet wide. The second posta on the road to Buenos Ayres stands on its banks; a little above there is a pass for horses, where the water does not reach to the horse's belly; but from that point, in its course to the sea, it is quite impassable, and hence makes a most useful barrier against the Indians.