Paropamisadae (Gandhara and Kabul) and Arachosia (Kandahar)

Tarn (1922), The Greeks In Bactria And India Ed. 1st, p.100: "The Paropamisadae was not among the provinces ceded by Seleucus to Chandragupta [...] there is a passage from Eratosthenes, usually neglected, which seems plain enough. It says that, before Alexander, the Paropamisadae, Arachosia, and Gedrosia all stretched to the Indus; the reference is to the Achaemenid satrapies, and it implies that in Persian times the Paropamisadae and Gandhara were one satrapy. Alexander (it continues) took away from Iran the parts of these three satrapies which lay along the Indus and made of them separate [caroikia] (which must here mean governments or provinces); it was these which Seleucus ceded, being districts predominantly Indian in blood [...] Of the satrapy which Eratosthenes calls Paropamisadae Chandragupta got Gandhara, the land between the Kunar river and the Indus; this is certain, because Eratosthenes says that he did not get the whole, while the thorough evangelisation of Gandhara by Asoka shows that it belonged to the Mauryas. The boundary in Arachosia cannot be precisely defined; but, speaking very roughly, what Chandragupta got lay east of a line starting from the Kunar river and following the watershed to somewhere near Quetta and then going to the sea by Kalat and the Purali river; that will serve as an indication. The Paropamisadae itself was never Chandragupta’s."

See this map for Porali River.

Gedrosia:

V.A. Smith (1914), Early History of India,^[1]: "The satrapy of Gedrosia (or Gadrosia) extended far to the west, and probably only the eastern part of it was annexed by Chandragupta. The Malin range of mountains,Template:Efn-la which Alexander experienced such difficulty in crossing, would have furnished a natural boundary."

Eggermont, Pierre (1975) Alexander's Campaigns in Sind and Baluchistan and the Siege of the Brahman Town of Harmatelia, Peeters Publishers p.58 describes the area, stating that the Malan range is an offshoot of the Makran Coastal Range, which was explored by Sir Aurel Stein, who found out that "the Buzelak, or "Goat's Pass", leading from the Malan plain across the Malan range into the plain of Ormara proved to be very steep," concluding that it was unlikely that Alexander had passed over the Malan range.

Cummings, Lewis Vance (2004) Alexander the Great, Grove Press p.395-396 also gives a description of the struggles of Alexander's army at hteir retreat from India: "They turned west, reaching the mouth of the Tomerus (Hingol) River [...] Alexander, true to his tactical principles, prepared to advance along the coast [...] An unexpected obstacle arose to the continuance of the line of march. On the other side of the river loomed the utterly impossible barrier of the Malan (modern name) mountain range, its seaward end dropping abruptly and precipitately into the ater, and barring passage."