Final answer:
The provided material does not contain information about Buck or the Shepherdsons, and thus does not allow for an accurate answer to be given regarding Buck's opinion of the Shepherdsons' bravery.
Step-by-step explanation:
The question asks about Buck's opinion of the Shepherdsons' bravery. It seems the content provided does not directly answer this question, as there is no character named Buck, nor a mention of the Shepherdsons within the excerpts provided.
In the context of American literature, Buck is a character from Jack London's The Call of the Wild, which is unrelated to the examples you've shared. It appears there is a mix-up with the reference material or the text the question pertains to. Therefore, without the correct context or source material, we cannot accurately determine Buck's opinion of the Shepherdsons' bravery.
The provided text is from various sources, including 'Uncle Tom's Cabin' by Harriet Beecher Stowe, 'The Money Moon' by Jeffery Farnol, and 'Riders of the Purple Sage' by Zane Grey.
These texts depict different characters and their opinions, but none of them mention Buck or the Shepherdsons. Therefore, we cannot determine Buck's opinion of the Shepherdsons' bravery based on the provided information.