A 19-year-old transient from the Dixon area was arrested early Monday morning on a variety of charges after he was stopped in Vacaville while driving a stolen truck with a 12-gauge shotgun inside, police said.Vacaville police were notified at 3:50 a.m. that a GMC truck had been stolen from Dixon. At about 4:20 a.m., the truck was spotted on Nut Tree Parkway, near Harbison Drive. Police stopped the truck and detained the driver, Ian Morris. The shotgun inside the truck was determined to have been stolen, as were additional items found in the vehicle. Morris was arrested on charges of vehicle theft, possession of a controlled substance, felon in possession of a firearm, violation of probation and two warrants out of Solano County.