The building material used in walls and vaults is undressed stone and mortar, but at Sarvistân the stones are more carefully coursed than at Firûzâbâd. As far as can be judged from photographs, the vaults must have been built over a centering. They oversailed the walls as at Ukhaiḍir, while the semicircular door and window arches were set back from the jambs according to Dieulafoy’s restoration, and oversailed the walls according to the restoration of Flandin.[145] The side walls of the palace are broken by frequent doorways, and in the smaller dome windows were pierced through the drum.[146] The domes are built far more skilfully than those of Firûzâbâd. The zone which contains the squinch oversails the wall, standing flush with the outer edge of a small cornice adorned with a dog-tooth. The squinches are built with a proficiency which is in marked contrast with their rude prototypes at Firûzâbâd. They are divided from the dome by a second dog-tooth cornice, and the dome itself is constructed of light brick tiles.[147] This combination of the two materials is resorted to again at Ukhaiḍir. The niches in the columned chambers are covered with semi-domes which are set clumsily over the angles on very small squinches.[148] The Achaemenidizing plaster-work of Firûzâbâd is not repeated, but the dog-tooth is copied from the cornice under the dome in the older palace. It is significant that the cornices of Sarvistân have but one fillet instead of the two fillets of Firûzâbâd. A tendency to reduce the importance of horizontal decorations is characteristic of Sasanian and of Mohammadan work in Mesopotamia (see below, p. 130). Both for Firûzâbâd and for Sarvistân a minute re-examination is urgently needed, but the political conditions of the province of Fars are not favourable to archaeological research. Nor was the state of affairs ideal at Qaṣr-i-Shîrîn when I was there in April 1911, and I measured the palace of Khusrau to the tune of the whizzing of stray bullets. That they were not intended to hit me was due principally to the fortunate circumstance of my having been accredited by a powerful Kurdish ally on the Turkish side of the frontier to the leading Kurdish brigand, Kerîm Khân, on the Persian side. This fact rendered the situation more reassuring, but I was not tempted to prolong my stay beyond the five days which I devoted to the palaces, neither did I loiter over my work. It would have been difficult to push on further into the interior, or perhaps I should say that it would have been too expensive; for though Kerîm Khân would have provided me with an escort, he would have expected a small fortune in return for his protection, and perhaps it might fairly be urged that he would have deserved it. According to the information which has reached me from Baghdâd, matters have gone from bad to worse since the date of my visit, and the high road of the Sasanian kings has been definitely closed to traffic.