But who were these Mayans, and where did they obtain their knowledge of building? No race can develop the art of building in stone without leaving well-marked traces of its slow growth. First, there is the rough stone building, which would be traceable in heaps of crumbling rough-hewn stones where they had fallen. Next, would come that stage when they would learn to mortar the stones together, perhaps adding rude ornamentation on the exterior walls. Very slowly the roughness would give place to better-hewn stones; patterns in the ornamentation would be evolved; and finally you would get the same ornamentation all over the country, identical as is the decoration of such cities as Kabah, Chichen, and Uxmal. But there is no crude work in Yucatan. The unornamented buildings, such as the Akad-Tzib at Chichen, are obviously of the same date as the ornamented structures. They have the same form, the same finish of stone; and everything points to the fact that the plainness of buildings was deliberate and in some way in keeping with the purpose of the edifice. We have searched for the early stages of the Mayan building civilisation in the caves of Yucatan, where traces, if anywhere, of the embryonic efforts of the architects might be expected, but we searched in vain. Of those caves that have been inhabited there are but few that have any signs of building inside, and none with any traces of carvings. A typical cave of those which had been built in we found in Cozumel island; but it was almost certain that it had not been used as a habitation for any long period. Its front, which had stood exposed to weather and the intrusion of wild beasts, had been built up, with a doorway in the centre. Its floor of earth was found some four feet beneath the débris that had blown in and collected since its ancient occupiers had deserted it; and just under this level was found a small jar of beads and scattered around were potsherds in a layer of charcoal where the cave-dweller had done his cooking. It is the opinion of Mr. Henry C. Mercer (_Hill-Caves of Yucatan_: Philadelphia, 1896), who in 1896 examined most of the caves of the Southern Sierras, that they were not dwellings but mere halting-places of a wandering people. He could find in them no trace of an evolution of stone-building. Of those that had any kind of carving, he says "they are random, sketchy figures, many of which suggested pictographs of North American Indians. With a few exceptions there was little of the mannerism of Yucatan about them; and if they had been inscribed on a cliff-side on the Sasquehana or in Ohio, few of them would have seemed out of place."