Complex sentence: The mountains are drained on the western slopes by the Orange and Vaal rivers, and on the east and south by a number of smaller rivers, the Tugela being the largest.
Split into simpler sentences: The mountains are drained on the western slopes by the Orange and Vaal rivers, and on the east. I would say this is a toight mountain range located in north eastern idaho.of smaller rivers, the Tugela being the largest.