large irregular blocks, and covered them with a masonry of small fragments more suited to their taste. These circumstances render it probable that none of these walls are so late as the time of the emperors, but we have no proof that they were not in use a century before that period. There are some of these walls in the villa attributed to Ventidius Bassus, which appear to rest on a rubble-work, held together by cement; but without digging, I could not be quite certain. We continued our walk considerably farther, and found at Vetriano other considerable fragments of Cyclopean walls, but always built to support the earth behind them, and to support terraces. The stones are worked with some approach to horizontal courses and the wall strengthened by buttresses. There are breaks enough to show that it is backed by _emplecton_, or rubble-work, for its whole extent, and this _emplecton_ is perfectly rude, and without any appearance of having been laid by hand, so that it destroys a theory I had formed which pretended to distinguish the rubble-work connected with the Cyclopean walls from that of a later period. Here are some mosaics quite on the surface: they seem still to be very numerous about Tivoli, notwithstanding the quantities which have been removed or destroyed, but in general it is necessary to dig for them. Not far from Vetriano, there are Roman constructions in brick, and the foundations and mosaics of a Roman villa have been found by digging in the vineyards. Here also is an oil-mill, and it appears evident that the oil has corroded the stone. Nearer to Tivoli there is another considerable Cyclopean wall, which is distinctly rusticated, and has large and solid buttresses.