The square tower was originally faced with thick cement, and then covered with washes of colour, in the same manner as the walls of the Teocallis in the Quiché city of Utatlan upon which the faded colours are still visible. If the existing outer coating was the only one that had been given it would be reasonable to infer that the age of the tower was not great. But it happens that in those places where portions of the stucco have fallen, there have been numerous applications of colour, and therefore admitting that the latest may look bright and fresh, it is not possible to estimate the periods that may have elapsed between the dates of successive layers. Although I was at first inclined to think that the building could not be ancient, yet a more careful examination left the subject indeterminate. Any conclusions which may have been thought probable on account of the state of the walls and roofs are equally uncertain. With regard to this matter it is necessary to take into consideration certain existing conditions. Immediately behind the ruins are the slopes of the sierras which I traversed on the way from Tumbalá. They are covered with loose fragments of the limestones of which they are formed. These were the building materials used by the architects of the temples. Their small size and flat surface were suitable for the purpose, when combined with mortar, the mixing of which the Indians well understood. The walls of the monastery were made with layers of these flat stones bound together with quantities of this mortar. The outer faces were carefully arranged to receive a thick casing of cement, which was so hard and sound, that it is evident the builders must have had an accurate knowledge of the best proportions of the substances required for its composition. The cement had a smooth surface and in several places it was still perfect. The colours laid upon it are red, blue, yellow and white. They appear to have been made more or less vivid and varied in accordance with what was thought necessary to obtain good contrasts. The stucco figures and scrolls were skilfully designed, and were coloured in a manner which was harmonious and effective. The sound state of the cement where it is sheltered from the action of the rain is extraordinary. It is strange that in this tropical climate where, for half the year there are continuous and heavy rainfalls, the variations from the damp, close atmosphere in the summer to the dry season of winter should not have had a more destructive influence upon buildings, mainly composed of rubble and mortar.