The mountains of the Hindu Kush running from east to west form the northern boundary of the province, and are met at the north-east corner of the Chitral agency by the continuation of an outer chain of the Himalayas after it crosses the Indus above the Kagan valley.
The Great Barrier Reef forms the prominent feature off the north-east coast of Australia; its extent from north to south is 1200 m., and it is therefore the greatest of all coral reefs.
The highest point in the north-east group of the island (called Gallura) is Monte Limbara (4468 ft.), S.E.
Again, a totally different character belongs to the canals in North Brabant, and the east and north-east of Holland where, in the absence of great rivers, they form the only waterways which render possible the drainage of the fens and the export of peat; and unite the lesser streams with each other.
The other large Bolivian tributaries of the Mamore, all rising on the north-east flanks of the Andes, are the Chapare, Secure, Manique or Apere and Yacuma, the last draining a region of lakes and swamps north of the Sierra Chamaya.
The coastline of the Gulf of Mortvyi Kultuk on the north-east is, on the other hand, formed by a range of low calcareous hills, constituting the rampart of the Ust-Urt plateau, which intervenes between the Caspian and the Sea of Aral.
Towards the north-west it borders on the Median district of Paraetacene (about Isfahan); towards the north and north-east it soon passes into the great desert, of which only the oasis of Yezd (Isatichai in Ptolem.
The largest river is the Kan Kiang, which rises in the mountains in the south of the province and flows north-east to the Po-yang Lake.
Lord Curzon restored, at his own cost, the monument which formerly commemorated the massacre of the Black Hole, and a tablet let into the wall of the general post office indicates the position of the Black Hole in the north-east bastion of Fort.
The territories north and north-east of these Bantu kingdoms are inhabited by Nilotic negroes and up to 1909 were left almost unadministered, except in close vicinity to the Nile banks.