The architecture of the Phoenicians began with the fashioning of the native rock—so abundant in all parts of the country where they had settled themselves—into dwellings, temples, and tombs. The calcareous limestone, which is the chief geological formation along the Syrian coast, is worked with great ease; and it contains numerous fissures and caverns,[61] which a very moderate amount of labour and skill is capable of converting into fairly comfortable dwelling-places. It is probable that the first settlers found a refuge for a time in these natural grottos, which after a while they proceeded to improve and enlarge, thus obtaining a practical power of dealing with the material, and an experimental knowledge of its advantages and defects. But it was not long before these simple dwellings ceased to content them, and they were seized with an ambition to construct more elaborate edifices—edifices such as they must have seen in the lands through which they had passed on their way from the shores of the Persian Gulf to the seaboard of the Mediterranean. They could not at once, however, divest themselves of their acquired habits, and consequently, their earliest buildings continued to have, in part, the character of rock dwellings, while in part they were constructions of the more ordinary and regular type. The remains of a dwelling-house at Amrith,[62] the ancient Marathus, offer a remarkable example of this intermixture of styles. The rock has been cut away so as to leave standing two parallel walls 33 yards long, 19 feet high, and 2 1/2 feet thick, which are united by transverse party-walls formed in the same way.[63] Windows and doorways are cut in the walls, some square at top, some arched. At the two ends the main walls were united partly by the native rock, partly by masonry. The northern wall was built of masonry from the very foundation, the southern consisted for a portion of its height of the native rock, while above that were several courses of stones carrying it up further. At Aradus and at Sidon, similarly, the town walls are formed in many places of native rock, squared and smoothed, up to a certain height, after which courses of stone succeed each other in the ordinary fashion. It is as if the Phoenician builders could not break themselves of an inveterate habit, and rather than disuse it entirely submitted to an intermixture which was not without a certain amount of awkwardness.