With the exception of a high dado, itself very beautiful, made of marble slabs with bands of mosaic between them, the whole interior surface of the walls, including soffits and jambs of all the arches, is covered with minute mosaic-pictures in brilliant colours on a gold ground.
It is cruciform in shape, and the walls are built mainly of flint, but jambs and arches are formed of Roman bricks.
The jambs were of dressed stone, usually plain, and the longer lintels were of zapote wood; some of them, where protected from the weather, are still to be seen, sometimes covered with inscriptions.
There is less stone carving on the exterior walls, door jambs and pillars of the buildings than on those of the Yucatan Peninsula; this is due to the harder and more uneven character of the limestone.
The inscriptions on the two jambs of a door are frequently turned in opposite directions; the same is frequently done with acti 1,, i the short inscriptions scattered over a scene on o an amongst the figures, in order to distinguish one or armj label from another.