It is on wood, moreover, that the first hieroglyphs must have been painted or cut. Many of them represented round objects or were formed of curved lines, which were transformed into a series of wedge-like indentations when imprinted by a stylus upon clay. We know, therefore, that clay was not the original writing material; its use as such, in fact, is coeval with the rise of that cursive script which, in the case of the Egyptian hieroglyphics, is called hieratic, but in Assyro-Babylonian is known as cuneiform. It was the attempt to reproduce the old pictures upon clay that created the cuneiform characters. As metal is not likely to have been employed by the primitive scribes of Chaldæa, and there is no trace of stone having been used--even the stone cylinder of later days being called a _dup-sar_ or “written tablet”--we are left to choose between wood and papyrus. In favour of papyrus is the fact that the circular forms of so many of the pictures suggest that they were originally painted rather than engraved; on the other hand, it is doubtful whether the papyrus grows in the Babylonian rivers, or at any rate did so in the prehistoric age. And the pictograph of a “written document” is not a strip or roll of papyrus, as in Egypt, but a tablet with a handle or loop. It is true that the primeval picture which denoted “copper” has much the same form, but as even cutting instruments had the determinative of “wood” attached to them in the early picture writing, it is clear that the original tablet could not have been of metal, whatever might have been the case with its later successors. The picture, moreover, of the “tablet” is distinguished from that of a “plate of bronze” by the addition of a string which is tied to the handle. On the whole, therefore, the only archæological evidence available at present is on the side of the tradition which made Babylonian culture move northward from the coast. The only fact against it of which I know is that, as I have already stated, the word for land was symbolized by the picture of a triple mountain. But this fact is not insuperable. Before the silting up of the shore, the old coast-line of Babylonia would have stretched away north-eastward of Eridu towards the mountains of Elam. Whether the mountains that fringed what would then have been the eastern coast of the Persian Gulf are visible from the site of Eridu, I do not know; if the clear light of Upper Egypt exists there they would be so. Nor do I know whether on the western side there are mountain ranges visible in Arabia; these are points which can be cleared up only when the country has been thoroughly explored.