Without entering into the details of M. Reichard's reasoning in support of this hypothesis, which is often somewhat hazardous and uncertain, it may be sufficient for the present purpose to observe, that his principal argument is founded on a consideration of the peculiar character belonging to the tract of country situated between the two rivers, which consists of a vast tract of low, level land, projecting considerably into the sea, and intersected by an infinity of small branches from the principal rivers. In these and other respects, it appears to bear a considerable resemblance, according to the best descriptions of that coast which we possess, to the Deltas at the mouths of the Nile, the Ganges, and such other great rivers, as by depositing large quantities of alluvial matter previous to their discharge into the sea, form gradual additions to the coast. For it may be proper in this place to remark, that the formation of Deltas, even by rivers of the first magnitude, is by no means universal; some of the greatest that are known being without them. Of this the Amazon, Plata, and Oronoko are mentioned by Major Rennell as distinguished instances; to which may now be added, the Congo. The difference appears to be owing to the depth of the sea at the mouth of the rivers, and perhaps to other circumstances, which are not quite understood. [Footnote: See Reunell's Geogr. System of Herodotus, 4to. p. 483.] Both of the two rivers, enclosing the great alluvial tract which has been described (the Rio del Rey and the Formoso), are stated to be of considerable size, being each of them seven or eight miles broad at the mouth; and the supposed Delta, estimated by the line of coast, is much larger than that of the Ganges: consequently, the two streams, if united, must form a river of prodigious magnitude. But neither of the rivers has ever yet been explored; nor has the interior of the country, to any distance from the coast, been accurately described by any European traveller. Hence, the question whether the two rivers are ever really united, and whether the tract in question is a complete Delta or not, still remains to be ascertained. With regard also to the course, or even the existence, of the great river to which this Delta is said to belong, and which M. Reichard supposes to come from the northeast of Africa, there is no tradition nor any vestige among travellers or geographical writers; the whole is purely conjectural. But the supposition, so far at least as relates to the alluvial origin of the tract in question and the junction of the two rivers, has great appearance of probability.