Strabo Geography 15.1.35

[35] A letter of Craterus to his mother Aristopatra is circulated, which contains many other singular circumstances, and differs from every other writer, particularly in saying that Alexander advanced as far as the Ganges. Craterus says, that he himself saw the river, and the whales ¹ which it produces, and [his account] of its magnitude, breadth, and depth, far exceeds, rather than approximates, probability. For that the Ganges is the largest of known rivers in the three continents, it is generally agreed; next to this is the Indus; and, thirdly, the Danube; and, fourthly, the Nile. But different authors differ in their account of it, some assigning 30, others 3 stadia, as the least breadth. But Megasthenes says that its ordinary width is 100 stadia, ² and its least depth twenty orguiae. ³