The platform at Persepolis is built at the foot of a high range of rocky hills, on which it abuts towards the east.  It is composed of solid masses of hewn stone, which were united by metal clamps, probably of iron or lead.  The masses were not cut to a uniform size, nor even always to a right angle, but were fitted together with a certain amount of irregularity, which will be the best understood from the woodcut overleaf.  Many of the blocks were of enormous size; and their quarrying, transport, and elevation to their present places, imply very considerable mechanical skill.  They were laid so as to form a perfectly smooth perpendicular wall, the least height of which above the plain below is twenty feet.  The outline of the platform was somewhat irregular.  Speaking roughly, we may call it an oblong square, with a breadth about two thirds of its length; but this description, unless qualified, will give an idea of far greater uniformity than actually prevails. [PLATE XL., Fig. 1.] The most serious irregularity is on the north side, the general line of which is not parallel to the south side, nor at right angles with the western one, but forms with the general line of the western an angle of about eighty degrees.  The cause of this deviation lay probably in the fact that, on this side, a low rocky spur ran out from the mountain-range in this direction, and that it was thought desirable to accommodate the line of the structure to the natural irregularities of the ground.  In addition to the irregularity of general outline thus produced, there is another of such perpetual occurrence that it must be regarded as an essential element of the original design, and therefore probably as approving itself to the artistic notions of the builder.  This is the occurrence of frequent angular projections and indentations, which we remark on all three sides of the platform equally, and which would therefore seem to have been regarded in Persia, no less than in Assyria, as ornamental.

[Illustration:  PLATE XL.]

The whole of the platform is not of a uniform height.  On the contrary, it seems to have been composed, as originally built, of several quite distinct terraces.  Three of these still remain, exhibiting towards the west a very marked difference of elevation.  The lowest of the three is on the south side, and it may therefore be termed the Southern Terrace.  It extends from east to west a distance of about 800 feet, with a width of about 170 or 180, and has an elevation above the plain of from twenty to twenty-three feet.  Opposite to this, on the northern side of the platform, is a second terrace, more than three times the breadth of the southern one, which may be called, by way of distinction, the Northern Terrace.  This has an elevation above the plain of thirty-five feet.  Intermediate between these two is the great Central or Upper Terrace, standing forty-five feet above the plain, having a length of 770 feet along the west face of the platform, and a width of about 400.  Upon this Upper Terrace were situated almost all the great and important buildings.