As hitherto remarked, it was the architect's intention to close the southern as well as the northern intercolumniation of the west wall but he was prevented, apparently for some religious reason. Now it seems very probable that the unusual construction at the corner is the result of an attempt to build a substitute wall for that which could not be placed in the southern intercolumniation. Two considerations favor this explanation. In the first place the horizontal slab inclines toward the opening. The certain purpose of this inclination was to shed rain-water. Secondly, traces on the south wall show that the metopon was coextensive in height with the opening and projected along the eastern edge of the horizontal slab. The epistyle of the metopon, which appears in the restoration (_A. J. A._, 1908, fig. 6, p. 196) is purely a conjecture and may be eliminated. But how far did this metopon project into the building? Was it coextensive in width as well as in height with the opening? The distance which the metopon projected into the building is not certainly known. In the restoration it is given as one foot but this is a calculation based on a combination of probabilities. The obvious provision to keep out rain-water, if it was to be successful, demands the extension of the metopon to the inner corner of the horizontal slab. But this slab unsupported could not have carried a marble metopon. This is a difficulty which seems to compel the assumption that the metopon was in part of lighter material.
Apart from serving the purpose of keeping out rain, the conjectured metopon would also be a counterpart to the northern intercolumniation when the façade was viewed from the west. The increase in weight due to the metopon and the horizontal slab necessitated a counterbalancing reduction in the weight of the south wall because of its insecure foundations. The idea, in short, is simply this. Just as when the architect was not allowed to place the west façade where he wished and retreated to a line at which he was allowed to build it in a necessarily modified form, so when he could not build a wall in the southern intercolumniation of that façade, he withdrew still farther back and built a substitute at the line allowed. The extra weight thus produced was partly responsible for the thinning of the insecurely founded south wall.