Alexander found that the river Indus discharges itself into the Great Sea by two mouths which are separated by 1800 stadia, and learnt that it has no connection with the Egyptian country. When he was approaching the mouth of the Indus, he saw a great lake formed by discharge of streams of different rivers into it. This has been identified by some scholars as Narayana Sara of Indian puranas, but did not speak much on it. He took help of the Phoenicians, Cyprians, Karians, and the Egyptians to enter into the Great Sea.

Alexander and Poros met at the opposite banks of the river Hydaspes; Poros was on its left bank; and here he was defeated by Alexander’s army. The place where Alexander built a town in the name of Bucephalus, i.e. ox-head, carried the name of his horse, and it was on the bank of this river. Ox-head itself marks the Greek region, where according to puranas, the river Go-mati, and G-sringa, or Go-mantaka mountain, and Go-karna jointly explain its complete geographical situation.

Alexander appointed Poros as the King of the Indians under whom as noted by Alexander’s historians was more than 2000 cities and seven nations. Along both the banks of the Hydaspes, his army marched towards the settlements of the Sopeithes. They were a group of wonderful people of the ancient world to whom Alexander liked very much because of their realistic approach to life and society. Sopeithes is identified as Sobhavati or Saravati, of Pali literature; this is also identical with Subhastu, and thus, marks the river Saraswati with Siddhapura.

The Mountain of fossil salt was then located in the land of the Sopeithes lying in between the upper Hydraotes and the Hyphasis. The salt mountain was sufficient to feed the whole of India with salt. This mountain which Pliny calls as Mt Oromenus(xxxi,39) extended from the Indus to the Hydaspes. Hyphasis marks the limit of Alexander’s expedition to India. Some scholars mark this spot as the limit of the ‘East’.  Here he raised an altar and sacrificed one of the elephants of Poros to Sun, which first deserted Poros, and he called this in the name of Ajax. Havens of Sun was a part of Taprobane along with the mouth and the source of the river Phasi.

There seems a difference of opinion on the place where Coenus died; authors find fault with Curtius who said it was a spot on the bank of the river Acesines instead of Hydaspes as noted in some other accounts. It is not an error because the two rivers coming together and flowing very close to each other makes this difference of little geographical value as their plains are closely knitted with the river Indus.

Regarding voyage of Alexander in the Indus which took five months, there again is observed a divided opinion among scholars. Pliny says(vi, 17) that though Alexander sailed  6000 stadia per day, he took more than five months to complete the navigation of this river. Scholars calculate thus the length of Indus to be 12,000 miles!. The distance, it is said, from the starting point to the sea, is between eight and 900 British miles. This is not the actual length of the river Indus. Alexander’s historians have clearly noted that the foot soldiers were always helped by soldiers in the ships and always moving in the same direction who kept themselves at a defined distance of only fifty to sixty miles from them. Very often river Indus crossed its banks due to inundation. This must have caused Alexander to stop his voyage for months.