In many parts of the world there are to be found monuments of rough, unhewn stones, sometimes rudely shaped by hammering, which from the size of the stones used have been termed megalithic monuments.[126] These consist of burial chambers, either a simple slab or capstone supported on four or more uprights, or a similar but more complex chamber, approached by a stone-lined passage. Other monuments consist of circles or alignments of standing stones, or single stones only set in an upright position. There are many types; some, like the dolmen or simplest burial chamber, or the simple standing stone, are widely distributed, while others have a restricted range. One type of elaborate temple is found only in Malta and in the adjacent island of Gozo.[127] Such monuments have these features in common: the stones are large, they have not been hewn with chisels or axes, and they are orthostatic or set on end. Frequently associated with these megalithic monuments are other structures, which are believed to belong to the same culture, though the association is not so clearly established. Such are bee-hive huts, round towers, and dry walls with polygonal masonry. These are often found in close association with the erections of larger stones, but not infrequently where true megalithic structures are absent.[128] An attempt has been made to show that the dolmen originated in Egypt, and is closely connected with the _mastaba_, the tomb used throughout the earliest dynasties.[129] Elsewhere I have endeavoured to show that there are reasons why we cannot attribute the origin of these structures to the inhabitants of the Nile Valley, and that the resemblances may better be explained by supposing that the idea of the former was introduced into Egypt, perhaps at the beginning of the second predynastic period, from some region, such as Syria, where dolmens were known, or else that both had been derived from a common ancestry.[130]