(ZNS) Most government officials and oil industry executives have been dismissing suggestions that the cost of gasoline could reach a dollar a gallon in the near future. But not J. K. Jamieson. Jamieson told the economie club of Detroit this week that he would not be at all surprised if gas cost at least a buck a gallon within the next six months. And Jamieson ought to know. He is the chairman and chief executive officer of Exxon, the largest oil corporation in the world.