Redactive analysis: While verse 22 of chapter 10 serves as a closure statement for the text preceding it, it is also a transitional verse for the one which follows. In verse 10:22 Nephi states that the Holy Ghost gives him authority, in verse 11:1 he begins by saying "For it came to pass. . ." Verse 1 of chapter 11 is the evidence of the assertion Nephi makes in 10:22 that the Holy Ghost has authorized his words.
Scriptural analysis: Nephi begins to relate a tremendous spiritual experience. It is significant to note that the experience does not begin until after Nephi "sat pondering in mine heart. . ." The message for us all is clear, the Lord will inspire and lead us, but we are required to make the initial effort. We too must ponder before the understanding of the heavens are opened to us.
Symbolic analysis: Nephi is caught away in spirit to an exceedingly high mountain. Why is that? What Nephi wants to see is a vision of things in a valley, not a mountain. Why does the vision begin there?
Mountains are sacred places in Hebrew cosmology. They form a symbolic world axis (and are therefore symbolically similar to the world tree symbol). The tops of the mountains are conceptually in the heavens, and are therefore a logical place for meetings with deity (or the Spirit!). Moses meets with God on a mountain, which serves as a sacred symbolic place. In Nephi's dream the journey to the mountain reinforced Nephi's understanding of the nature of the guide who took him there. Symbolically, Nephi knows that he has entered upon sacred ground, and a fit place for the presence foo the Spirit of the Lord.