Mr Carter,Mr Butler,Mr Drover and Mr Hunter are employed as a carter,a butler,a drover and a hunter.None of them has the

Mr Carter,Mr Butler,Mr Drover and Mr Hunter are employed as a carter,a butler,a drover and a hunter.None of them has the name of his profession.They made four statements:
1.Mr Carter is the hunter.
2.Mr Drover is the carter.
3.Mr Butler is not the hunter.
4.Mr Hunter is not the butler.
According to these statements,the butler must be Mr Butler,but this cannot be correct.Three of the four statements are not ture .Who is the drover?