TN Rubble Strips and CobblestonesWe stock TN Flagstone Brown and Gray Tumbled Cobblestones. The average size of the flagstone cobbles are ~ 4"x4"x8". You will get approximately 80 90 linear feet per ton or 55 square feet per ton. We stock TN Flagstone Brown and Gray Rubble Strips. These vary in length from 4" 30" and will range in thickness from 3" 6". You will get approximately 80 90 linear feet per ton.