Jacksonville police this afternoon identified a boy killed Friday in a collision between his dirt bike and a Jeep as Charles S. Bowcock IV, 15, of Shipwreck Drive. The accident occurred about 8 p.m. at 12701 Beach Blvd. Police said Bowcock was driving a mini-bike south on a dirt road on private property and collided with a Jeep Wrangler traveling northeast on another dirt path.