Guided tours through the mill, passing the leather belts that turn the shafts and over the wood shavings that scatter the floor, give an account of life at the mill during Victorian times.
The tours help describe what the mills were like. 
mnli hypothesis: The tours help describe what the mills were like.  premise: Guided tours through the mill, passing the leather belts that turn the shafts and over the wood shavings that scatter the floor, give an account of life at the mill during Victorian times.