the marc strait is a gap through the toba kakar pass of mountains on the border of pakistan . the english approached the threat of a russian penetration of india via the khyber and bolan passes very seriously so in 1837 , a british envoy was send to kabul to gain supporters of the amir , dost muhammad . in february of 1839 , the british army under sir john keane sent 12 , 000 men through the mack pass and entered kandahar .
The British Army crossed the Toba Kakar Range of mountains in 1839.