The mill had not yet started operations.

Tom got off and looked the property over, consulted his map, then the journey was resumed.

Just beyond the mill they came upon another of the now familiar blazes, directing them to proceed to the right and follow the river bank.
"The blazer fellow evidently knows where we wish to go.

Do you know where we are, Mrs.Shafto ?" called Tom.
"Yes, I know now.

It's the Little Big Branch River, though it ain't much of a river yit.