Firefighters from Marne, Atlantic, Lewis and Hancock were called to assist with a structure fire in rural Walnut, at around 4:30-a.m. today (Thursday). The blaze, which was reported by passing motorists, occurred  at 50507 Sumac Road. According to dispatch reports, a barn was fully engulfed in flames and had collapsed by 5-a.m., and the flames were near some other structures. Fire crews saved two adjacent structures, but the barn was a total loss. A cause of the fire remained under investigation.