We left Olho d’Agoa in the afternoon, and shortly afterwards entered a country very similar to that between Icó and Crato, but as the rain had been falling for nearly a month, everything was quite green. The rapidity with which vegetation advances in these deserts, after the first few showers, is quite astonishing; the annual grasses spring up through the white sand, the trees burst into leaf and bloom, and the perennial herbaceous plants, which during the drought were apparently destroyed, throw up their flowering stems in an incredibly short period. In crossing a small stream on this journey I observed the rock, forming its bed, to consist of gneiss, cropping out towards the west; beyond this place sandstone again made its appearance, but scattered over it are an immense number of large angular blocks of gneiss. After travelling three leagues, we reached a place called Poço do Cavallo, and put up for the night at an unfinished house, which, though roofed over, was open at the sides. Besides ourselves two other travelling parties had also taken up their quarters here. In a marsh near us a whole legion of frogs were holding their nightly concert, and so loud was their noise, that I found some difficulty in going to sleep. Shortly before reaching this place, I collected specimens of a fine large tree which I afterwards found to be very common in the district; it belongs to the natural order _Meliaceæ_, and is called by the Brazilians Cedro, from the wood resembling both in colour and smell that of the true Cedar; the wood is very much used for making doors, tables, and various articles of furniture. The leaves and flowers possessed so strongly the odour of garlick, that the atmosphere was rendered disagreeable to breathe. The pastures for our horses were now excellent, the new grass being from four to six inches high, and very abundant. To the botanist it was quite delightful to travel through such a country, for nearly at every footstep something new and beautiful was added to my collections; the only drawback was the difficulty of preserving the specimens, owing to the great humidity of the atmosphere, and the want of proper means of drying the paper, as the sun now seldom shone out brightly.