366. Where the strata are nearly horizontal, they afford the most distinct information concerning the direction and progress of the wasting of the land. The inclined position of the strata, which in all other cases must enter for so much into our estimate of the causes which have produced the present inequality of the earth's surface, disappears there entirely; and the whole of that inequality is to be ascribed to the operations at the surface, whether they have been sudden or gradual. A very important fact from a country of this sort, is related by BARROW, in his Travels into Southern Africa. The mountains about the Cape of Good Hope, and as far to the north as that ingenious traveller prosecuted his journey, are chiefly of horizontal strata of sandstone and limestone, exhibiting the appearance, on their abrupt sides, of regular layers of masonry, of towers, fortifications, &c. Now, among all these mountains, he observed, that the high or steep sides look constantly down the rivers, while the sloping or inclined sides have just the opposite direction. When, in travelling northward, he passed the line of partition, where the waters from running south take their direction to the north, he found, that the gradual slope, which had hitherto been turned to the north, was now turned to the south: The abrupt aspect of the mountains, in like manner, from facing the south, was directed to the north; so that, in both cases, the hills turned their backs on the line of greatest elevation.[184] [Footnote 184: Barrow's Travels into Southern Africa, p. 245.] It is evident, therefore, that the form of this land has been determined by the slow working of the streams. The causes which produced the effects here described, began their action from the line of greatest elevation, and extended it from thence on both sides, in opposite directions. This is the most precise character that can mark the alluvial operations, and distinguish them from the overwhelming power of a great _debacle_. 367. Lastly, if there were any where a hill, or any large mass composed of broken and shapeless stones, thrown together like rubbish, and neither worked into gravel nor disposed with any regularity, we must ascribe it to some other cause than the ordinary _detritus_ and wasting of the land. This, however, has never yet occurred; and it seems best to wait till the phenomenon is observed, before we seek for the explanation of it.