3 Those who navigate the Red Sea— where we must pray that the true Pharaoh may be drowned with all his host— have to encounter many difficulties and dangers before they reach the city of Auxuma. Nomad savages and ferocious wild beasts haunt the shores on either side. Thus travellers must be always armed and on the alert, and they must carry with them a whole year's provisions. Moreover, so full are the waters of hidden reefs and impassable shoals that a look-out has constantly to be kept from the masthead to direct the helmsman how to shape his course.
They may count themselves fortunate if after six months they make the port of the above-mentioned city. At this point the ocean begins, to cross which a whole year hardly suffices. Then India is reached and the river Ganges— called in holy scripture Pison— “which compasses the whole land of Havilah” and is said to carry down with it— from its source in paradise— various dyes and pigments. Here are found rubies and emeralds, glowing pearls and gems of the first water, such as high born ladies passionately desire. There are also mountains of gold which however men cannot approach by reason of the griffins, dragons, and huge monsters which haunt them; for such are the guardians which avarice needs for its treasures.
Source: Letters (New Advent)