~The Southern Boundary.~--East of the Indus the frontier runs south-east for about fifty miles parting Sind from the Bahawalpur State, till a point is reached where Sind, Rajputana, and Bahawalpur join. A little further to the east is the southern extremity of Bahawalpur at 70 deg. 8' E. and 27 deg. 5' N. From this point a line drawn due east would at a distance of 370 miles pass a few miles to the north of the south end of Gurgaon and a few miles to the south of the border of the Narnaul tract of Patiala. Between Narnaul and the south-east corner of the Bahawalpur State the great Rajputana desert, mainly occupied in this quarter by Bikaner, thrusts northwards a huge wedge reaching almost up to the Sutlej. To the west of the wedge is Bahawalpur and to the east the British district of Hissar. The apex is less than 100 miles from Lahore, while a line drawn due south from that city to latitude 27'5 deg. north would exceed 270 miles in length. The Jaipur State lies to the south and west of Narnaul, while Gurgaon has across its southern frontiers Alwar and Bharatpur, and near the Jamna the Muttra district of the United Provinces. CHAPTER II MOUNTAINS, HILLS, AND PLAINS ~The Great Northern Rampart.~--The huge mountain rampart which guards the northern frontier of India thrusts out in the north-west a great bastion whose outer walls are the Hindu Kush and the Muztagh-Karakoram ranges. Behind the latter with a general trend from south-east to north-west are the great valley of the Indus to the point near Gilgit where it turns sharply to the south, and a succession of mountain chains and glens making up the Himalayan tract, through which the five rivers of the Panjab and the Jamna find their way to the plains. To meet trans-Indus extensions of the Himalaya the Hindu Kush pushes out from its main axis great spurs to the south, flanking the valleys which drain into the Indus either directly or through the Kabul river.