Shute Shelve Tunnel - Transition - Left side looking North

Shute Shelve Tunnel on the Strawberry Line Trail in Somerset and North Somerset, in the South West of England. (The tunnel is on the border between the two counties...)

The photo shows flow-stone forming on the transition between the unlined section where the old railway tunnel was cut through hard limestone and the brick and stone lining where the rock strata changes to soft marl.