Save for the clearing of our minds, the date of the early temple-foundations does not immediately concern us. Their importance is that, but for the building of the Parthenon, early and late, we should never apparently have had the great alteration and addition to the south side of the hill and the ancient Pelasgian wall would never have been covered in. Let us see how this happened[20]. We start with nothing but the natural rock, and on it the Pelasgian wall (1). Over the natural rock is a layer of earth, marked I. Whatever objects have been found in that layer date before the laying of the great foundations; these objects are chiefly fragments of pottery, many of them of ‘Mycenean’ character, and some ordinary black-figured vases. It is decided to build a great temple, and the foundations are to be laid. The ground slopes away somewhat rapidly, so the southern side of the temple is to be founded on an artificial platform. The trench (_b_) is dug in the layer of earth; then, just as on the north side of the hill, no scaffolding is used, but as the foundations are laid course by course, the _débris_ is used as a platform for the workmen. A supporting wall (2) is required and built of polygonal masonry; it rises course by course, corresponding with the platform of _débris_. And then, what might have been expected but was apparently not foreseen, happens. The slender wall can be raised no higher and at about the second course the _débris_ unsupported pours over it, as seen at III. The _débris_, unchecked, fell over as far as the old Pelasgian wall. How high this originally stood it is not possible now to say; but, from the fact that outside the supporting wall the layers of _débris_ again lie horizontally, and from the analogy of another section taken further west, which need not be discussed here, it is probable that the old wall was raised by several new courses, and that the higher ones were of quadrangular blocks, as restored in Fig. 7. So far all that has been accomplished is the raising of the old Pelasgian wall and a levelling up of the terrace to its new height. That these terraces were raised step by step with the foundations of the Parthenon is clear. Between each layer of earth and poros fragments—just as we have seen in the similar circumstances of the north wall (p. 15)—is interposed a layer of splinters and fragments of the stones used in the building of the foundations. This can clearly be seen at II. in the section in Fig. 7.