Moroni received and read the letter at the beginning of the thirtieth reign of the judges. He was very happy to receive this letter from Helaman “because of the welfare, yea, the exceeding success which Helaman had” He had not, until the letter came, known much about what had actually been going on.
The most common writing material used in Mesoamerica and widely throughout the western hemisphere was fig bark or a tree bark that they would cut, peel off, smooth out and dry. It made quite a good writing surface. It was smooth and when it dried, it was like a good parchment, and was quite durable. They would stitch pieces together and stack them to make accordion folds, so it was all in one piece. The runner was not carrying a big flier. The Spaniards thought that these documents were all pagan, so they burned thousands and thousands of them, which is a real catastrophe. They proudly reported that they were eradicating all the pagan beliefs.
John L. Sorenson, “The Book of Mormon as a Mesoamerican Record,” in Book of Mormon Authorship Revisited: The Evidence for Ancient Origins, ed. Noel B. Reynolds (Provo, UT: Foundation for Ancient Research and Mormon Studies, 1997), 391–521.