"In the basin of Matongo, in Southern Urimi, we were instructed by the ruins and ridges, relics of a loftier upland, of what has been effected by nature in the course of long ages. No learned geological savant need ever expound to the traveler who views these rocky ruins, the geological history of this country. From a distance we viewed the glistening naked and riven rocks as a singular scene; but when we stood among them, and noted the appearance of the rocky fragments of granite, gneiss and porphyry peeled as it were rind after rind, or leaf after leaf, like an artichoke, until the rock was wasted away, it seemed as if Dame Nature has left these relics, these hilly skeletons, to demonstrate her laws and career. It seemed to me as if she said, 'Lo, and behold this broad basin of Matongo, with its teeming villages and herds of cattle and fields of corn, surrounded by these bare rocks--in primeval time this land was covered with water, it was the bed of a vast sea. The waters were dried, leaving a wide expanse of level land, upon which I caused heavy rains to fall five months out of each year during all the ages that have elapsed since first the hot sunshine fell upon the soil. The rains washed away the loose sand and made deep furrows in course of time, until in certain places the rocky kernel under the soil began to appear. The furrows became enlarged, the waters frittered away their banks and conveyed the earth away to lower levels, through which it wore away a channel, first through the soil and lastly through the rock itself, which you may see if you but walk to the bottom of that basin. You will there behold a channel worn through the solid rock some fifty feet in depth; and as you look on that you will have some idea of the power and force of the tropical rains. It is through that channel that the soil robbed from these rocks has been carried away toward the Nyanza to fill its depths and in time make dry land of it. Now you may ask how came these once solid rocks, which are now but skeletons of hills and stony heaps, to be thus split into so many fragments? Have you never seen the effect of water thrown upon lime? The solid rocks have been broken or peeled in an almost similar manner. The tropic sun heated the face of these rocks to an intense heat, and the cold rain falling upon the heated surface caused them to split and peel as you see them.'