The Question and Answer section for Journey to the Center of the Earth is a great resource to ask questions, find answers, and discuss the novel.
As Axel is the story's narrator, I see no evidence of him providing a physical description of himself. He does, however, give a detailed description of his uncle. Did your question have a corresponding chapter number?
Since there isn't a character by the name of Trevor in the novel, I will assume you're referring to the movie. Note, this is a short-answer literature forum designed for text specific questions. Fortunately, this answer was quickly found....,
I'm sorry, this is a short-answer literature forum. We are unable to answer questions about motion picture adaptations unless otherwise noted in the category.