Johnston was invited several years ago to begin a study of the hidden house mounds at El Mirador in an attempt to re-‐define the demographic densities of ancient major cities. A “hidden” house mound is a residence with perishable roof and side walls, and a packed earthen floor, similar to what the majority of inhabitants in the Peten have today, which has been abandoned, deteriorated, and is buried under a few centimeters of jungle soils with no surface indications of its existence.
Example of a hidden house mound: A packed earthen floor with Preclassic ceramics still in place on the floor of the structure. A perishable roof and wooden posts formed the boundaries of the structure, but which leave no surface indications of their existence after abandonment. (Photo: R.D. Hansen)