Answer :
Final answer:
Stevenson introduces themes of treasure and mystery to engage readers in an adventure story.
Explanation:
Stevenson's reason for beginning the chapter with the mentioned paragraph is to create interest in the reader by introducing the themes of undiscovered treasure and the arrival of a mysterious character. The mention of still buried treasure and the arrival of a brown old seaman with a sabre cut sets the stage for an intriguing adventure story that will unfold.
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