The elevation gradually increases in advancing towards the equator; and the soil, on approaching Delow, where the northernmost point of the Mandara chain commences, is covered with a glittering micaceous sand, principally decomposed granite, which forms a productive earth. The hills extend in apparently interminable ridges east-south-east, south-west, and west; while to the south several masses or systems of hills, if I may so express myself, spread themselves out in almost every picturesque form and direction that can be imagined. Those nearest the eye apparently do not exceed 2500 feet in height; but the towering peaks which appear in the distance are several thousand feet higher. They are composed of enormous blocks of granite, both detached and reclining on each other, presenting the most rugged faces and sides. The interstices and fissures appeared to be filled with a yellow quartzose earth, in which were growing mosses and lichens: trees of considerable size also grow from between them. On almost all the hills that I approached, clusters of huts were seen in several places towards the centre, and sometimes quite at the summit; generally on the flats of the ridges. At the base of these mountains, and also at a considerable elevation on their sides, are incumbent masses of what appeared to be the decomposed fragments of primitive rocks recompounded, and united anew by a species of natural cement. At some distance from the base of those which I ascended from the valley of Mora, were collections of quartzose rocks, of great variety and colour; fragments of hornblende, and several large abutments of porphyroidal rocks. About one hundred yards above the spring which I have before mentioned, in a space between two projecting masses of rock, were numerous shells, some petrified and finely preserved, while others were perforated by insects, worm-eaten, and destroyed: they were confusedly mixed with fragments of granite, quartz, sand and clay; and in some cases adhered to pieces of the composition rocks: the greater part were of the oyster kind. Various specimens of these, with pieces of every variety of the structure of the hills, I had collected, but they were all lost in the general confusion of the battle; and on the return of the army I was unable to do more than procure a few specimens of the northernmost part of the mountains; and the half of these were lost by my negro.