(1) The cement work of the oldest periods has been pronounced by practical builders to have been made of crushed fragments of decomposed granite mixed with a large proportion of lime, the latter being found in Suku Glen (see _Suku Glen_) in extensive areas. This cement is exceedingly hard, and has a glaze on the outer surface which, once broken, has caused the internal body of cement to rapidly decompose into yellow soil. Thus on the faces of steps, dadoes, and all perpendicular work, the cement is more intact, while on flat surfaces where rain-water could not be carried away owing to the stopping up of drains the cement floors are in many instances considerably ruined. Tree roots are rarely found to have penetrated any cement floor which was in a whole condition, and where a root has so penetrated the cement, the root, acting as a conductor of water, has caused all the cement along the line of root to become decomposed. All the roots of trees which have recently been removed from above cement floors are flat, while some of them assume the shape of the structure that was underneath. In one instance the roots of an immense fig tree, which was thought to be over one hundred years old, had wound round and round a circular cement platform which they had failed to penetrate. This class of cement has been very extensively used by the older occupiers for (_a_) flooring, (_b_) dadoes, (_c_) covering steps and platforms, (_d_) construction of steps and platforms made entirely of cement, (_e_) raised rims for dividing floors into separate catchment areas, so confining rain-water over certain areas to particular drains, (_f_) foundations of walls, (_g_) for short, low divisional walls made entirely of cement. (2) There is another class of granite cement which closely resembles the first-mentioned, and this is found on the higher levels. It is also yellow, but in it occur pieces of granite, and it has a decidedly coarser appearance. This is not so lavishly laid, being only one or two inches thick, whereas the former cement is most frequently found to have a thickness of at least 6 in., that is, in those instances where the structures are not entirely composed of this cement. A great quantity of this cement work can be seen on the Acropolis or in the Valley of Ruins. (3) A further class of cement is of a dull reddish colour, containing more soil than granite. Practically it is clay, but so fine and well polished that it deserves the designation of cement. This work had been burnt white, and its material is very strong and far superior to the best clay used by the oldest native occupiers.