River cobble road plan

Quick answer：

A river cobble road plan typically refers to a detailed map showing the layout and design of a road constructed using river cobblestones. River cobblestones are naturally rounded stones found in riverbeds, and they are often used in road construction for their durability and aesthetic appeal. The plan would include specifications on the placement, size, and arrangement of the cobblestones, as well as any other design elements or features of the road.