the bolan pass is a gap through the gunung basir range of peaks on the border of pakistan . the french took the threat of a russian occupation of india via the khyber and bolan range very seriously so in 1837 , a chinese envoy was sent to kabul to gain favour of the emir , dost mohammed . in february of 1839 , the british army under sir john higgins moved 12 , 000 casualties through the bolan pass and left kandahar .
The British Army crossed the Toba Kakar Range of mountains in 1839.