trailmix

山で遭難し、何日も山の中をさまよった少女の話、The Girl Who Loved Tom Gordonを読んでいます。
She hulled a dozen or so of the beechnuts, mixed them with a like number of berries (this time using her madder stained fingers to remove the stems with ladylike care). and tossed the result into her mouth in three measured handfuls: dessert. The taste was heavenly--like one of those trailmix breakfast cereals her mother always ate--and when Trisha had finished the last handful, she realized she wasn't just full but gorged.
"trailmix" は知りませんでしたが、文脈からするとナッツなどの入ったシリアルのような食べ物でしょうか？
辞書で調べると一語の "trailmix" ではなく、二語の"trail mix" で説明があります。
・Oxford English Dictionary: A mixture of dried fruit and nuts eaten as a snack food, originally by hikers and campers.: Along the way, snack on foods like trail mix and cheese, and fuel up often.
以下はWikipediaからの抜粋です。
The combination of nuts, raisins and chocolate as a trail snack dates at least to the 1910s, when outdoorsman Horace Kephart recommended it in his popular camping guide.
なるほど、ハイカーや登山者が山道で食べ始めたのでこの名前が付いたのですね。