The Spanish Peninsula also possesses rock-hewn tombs. At Palmella, near Lisbon, is a circular example about 12 feet in diameter preceded by a bell-shaped passage which slopes slightly downwards. Another circular chamber in the same group has a much longer passage, which bulges out into two small rounded antechambers. These tombs have been excavated and yielded some pottery vases, together with objects of copper and beads of a peculiar precious stone called _callais_. All the finds made in the megalithic remains of Spain and Portugal point to the period of transition from the age of stone to that of metal. The Balearic Islands contain remarkable megalithic monuments. Those known as the _talayots_ are towers having a circular or rarely a square base and sloping slightly inwards as they rise. The largest is 50 feet in diameter. The stones, which are rather large and occasionally trimmed, are laid flat, not on edge. A doorway just large enough to be entered with comfort leads through the thickness of the wall into a round chamber roofed by corbelling, with the assistance sometimes of one or more pillars. From analogy with the _nuraghi_ of Sardinia, which they resemble rather closely, it seems probable that the _talayots_ are fortified dwellings, perhaps only used in time of danger (Fig. 15). [Illustration: Fig. 15. Section and plan of the Talayot of Sa Aquila, Majorca. (After Cartailhac.)] [Illustration: Fig. 16. Nau d'Es Tudons, plan and section. (After Cartailhac.)] The _naus_ or _navetas_ are so named from their resemblance to ships. The construction is similar to that of the _talayots_. The outer wall has a considerable batter. The famous Nau d'Es Tudons is about 36 feet in length. The facade is slightly concave. A low door (_a_) gives access through a narrow slab-roofed passage (_b_) to a long rectangular chamber (_c_), the method of whose roofing is uncertain. All the _naus_ are built with their facades to the south or south-east, with the exception of that of Benigaus Nou, the inner end of which is cut in the rock, while the outer part is built up of blocks as usual. The abnormal orientation was here clearly determined by the desire to make use of the face of rock in the construction. The _naus_ seem to have been tombs, as human remains have been found in them. Rock-tombs also occur in the islands. The most remarkable are those of S. Vincent in Majorca. One of these has a kind of open antechamber cut in the rock, and is exactly similar in plan to the Grotte des Fees in France (cf. Fig. 12).