Answer:
The two excerpts that create a dreary mood in the passage are:
1. “A few rough logs, laid side by side, served for a bridge over this stream. On that side of the road where the brook entered the wood, a group of oaks and chestnuts, matted thick with wild grapevines, threw a cavernous gloom over it.” This excerpt creates a dreary mood by describing the dark and gloomy atmosphere of the woods.
2. “This has ever since been considered a haunted stream, and fearful are the feelings of the schoolboy who has to pass it alone after dark.” This excerpt creates a dreary mood by describing the fear and unease that people feel when they have to pass the haunted stream alone after dark.