MYRTLE CREEK — A traffic stop on Interstate 5 Thursday morning yielded 18 pounds of marijuana worth an estimated $40,000. The two men in the car are suspected of picking up the marijuana somewhere in California and planning to bring it to Washington, Myrtle Creek police said. Juan Manuel Gonzales, 28, and Nicholas Esquivel, 28, both of Mount Vernon, Wash., were arrested on suspicion of unlawful distribution of marijuana and unlawful possession of marijuana. Police Chief Don Brown said the amount seized was large, but no longer uncommon. The haul was well short of the 100-plus pounds that get federal …