According to John Sorenson, one should be careful in one's expectations of archaeological finds confirming huge walls that correspond to proposed Book of Mormon sites in Mesoamerica in every instance. For example, there was a huge stone wall built by the Spaniards in colonial days in the Valley of Mexico. They utilized over two million people in the project. But despite its historical recency and huge scale, no surviving traces of the structure have been noted by archaeologists or historians. The same is true of the six-mile long wall which the Tlaxcalans had built between them and their Aztec enemies and which Cortez described. It was huge, nine feet high and 20 feet thick with a breastwork atop it, yet no archaeologist has discovered any remnant of it, as far as is known.
A look at Zarahemla's wall according to the text is instructive. According to the book of Alma (see the commentaries on Alma 50:1-6; 53:4; 62:21-22), we might presume that excavated soil was thrown against a wall of upright timbers, yielding a cross-section, from outside to inside, or ditch, sloping face, and vertical inner face. The timber was to "the height of a man." However, we are nowhere told how long the wall at Zarahemla stretched nor how far it lay from the center of the city.
Additionally, after the Amalickiah/Moroni wars no mention is made of renewed needs for walls, although of course it is possible that they kept them up. (The failure of Zarahemla's wall to protect against Coriantumr's lightning attack (see Helaman 1:21-22) could have persuaded the Nephites that some of the walls were no longer worth the cost to maintain.) As soon as the timbers rotted without being replaced, the earth piled against them would have slumped inward. Erosion would subsequently spread the earth both into the ditch and over the inner surface until the remaining earthen bank would be only on the order of three feet high.
It is interesting that the initial finding of a fortified wall at the great Maya center of Tikal was accidental. What at first appeared to be merely a hillock and adjoining arroyo several miles from the site turned out to be weathered remnants of an earthen fortification wall and parallel ditch that stretched for miles. The little elevation was too slight to show up on an aerial photograph. Besides, at that time "everyone knew" that the Maya did not engage in wars,[86] so who was focused on fortifications? Unfortunately for the proposed site of Santa Rosa as the city of Zarahemla, the discovery of walls and warfare came after the archaeological work at Santa Rosa was finished and after the site was covered with water. [John L. Sorenson, "Viva Zapato! Hurray for the Shoe! in Review of Books on the Book of Mormon, Vol. 6, Num. 1, pp. 350-352]
Helaman 16:2 Many shot arrows at him [Samuel] as he stood upon the wall ([Illustration]): Samuel the Lamanite on the Wall. [The Church of Jesus Christ of Latter-day Saints, Gospel Art, #314]