The Delta tract, as taken in the _Memoir_, extends from the sea northwards to the latitude of Haidarâbâd (25° 25´ N.), and is bounded on the east by the desert, the Purân or old course of the Indus, now dry, and by the Korî mouth, which is the Lonibare mouth of Ptolemy; on the west by the outer border of the plains, where the boundary runs S. by W. for 50 miles to near Thata, from which point it turns almost due west, and runs for 60 miles more to the sea, near Karâchî. This alluvial tract is everywhere furrowed by ancient channels, some continuous, both above and throughout the Delta, and others all but totally obliterated. Our author has a notice of each of the more important of these channels. Regarding the Ghâro, the western arm down which Alexander and his fleet sailed, he says that it runs nearly east and west along the southern border of the Kohistân (hill-country), that it is thus on the extreme edge of the Delta, and that it has a course of about 40 miles in length. Referring to the present channel of the Indus, he remarks:— “This divides the lower Delta region into two unequal portions. Of these, the western, and much the smaller, portion is in the form of an equilateral triangle, having sides of about 64 miles in length, consisting of the river, the coast-line, and the southern edge of the Kohistân plains, and including an area of about 1700 square miles. This it will be convenient to call the ‘Western Delta,’ a name the more suitable that all the westward-flowing branches of the river have, or have once had, their mouths within the limits of the tract to which it will apply.” A very interesting question is next discussed—that of the secular extension of the Delta seaward—and the conclusion arrived at, which is, however, conjectural, and below the estimate of Colonel Holdich, is that from Alexander’s time to 1869 A.D. the advance of the Delta seaward has been eight miles, or at the rate of rather more than six yards in a year, this being less than a fourth of the growth of the Nile Delta in a not much greater period of time. We now proceed to show what new light we gain from the _Memoir_ respecting the voyage of Nearchos from the naval station in the Indus to Alexander’s Haven, now Karâchî. We abridge the account which Arrian has given in his _Indika_ of this part of the famous voyage:—