(Oregon City, OR)  --  Sheriff's deputies are trying to find out what caused a crash that killed an 18-year-old woman and critically injured a seven-year-old boy near Oregon City.  The crash took place around six p.m. Friday on South Redland Road near Lyons Road.  Deputies say Madison West veered into the oncoming lane and crashed into an oncoming vehicle.  West died later at a hospital, and the seven-year-old who was riding in the second vehicle is listed in critical condition.