When we reach our town and walk over it, much more can be seen of what is beneath. Very likely it seems all irregular, hillocky, dusty ground, and who can say what it may cover? In one place, however, we find that there are no chips or potsherds lying about: track around, and find the space of this clearance, probably it runs along for some distance; you are on the top of a mud-brick wall, denuded down to the level of the rubbish in which it is buried. Follow the clear space, and you will outline the fortifications of the city or its temple. Or perhaps you notice a difference in the vegetation--no plants will grow on particular ground; here is probably a mass of hard mud-brick or stonework, without moisture or nutriment, and you will thus find the walls. Or there is a hollow or old pit met with; here the modern natives have been digging out stone masonry, and around it, or below, may be the rest of a building. Some symmetrical form of the mounds can be detected, and we are perhaps led at once to the temple, or to trace out the streets of the town. Or a patch of ground is reddened with fire, showing that a house has been burnt there, and probably stone and metal and pottery may remain intact in the ruins. But our special notice must be given to the potsherds lying strewn all over the surface. Pottery is the very key to digging; to know the varieties of it, and the age of each, is the alphabet of work. Not that it is more distinctive in itself than most other products of various ages; but it is so vastly commoner than anything else, that a place may be dated in a minute by its pottery on the surface, which would require a month’s digging in the inside of it to discover as much from inscriptions or sculptures. A survey showing the form of the ground, and the position of every fragment or indication that can be of use, is essential to understanding it; and will often point out, by the probable symmetry of parts, what are the best spots to examine first.