LOFTUS TURKO-PERSIAN FRONTIER. 301 



Selmas would repay careful examination. The changes are rung on 

 the various minerals entering into their composition in the most ex- 

 traordinary and perplexing manner. At one locality near the summit 

 is a mass of grey syenite, containing magnetic oxide of iron. 



On the descent to the Chehrik stream the sandstones and gravels 

 of the gypsum-series again make their appearance, dipping at a 

 slight angle to the river and towards the north. Just before gaining 

 the river, a very interesting and remarkable phsenomenon presents 

 itself. The upturned edges of the sands and gravels are overlaid by 

 basalt ; — an overflow probably from the mountains on the west, form- 

 ing an extensive coulee over the whole upper part of the Plain of 

 Selmas*. The river itself flows between natural cliffs of about 

 300 feet in height, exposing a fine section. 



The basalt, which constitutes one half of the cliff, is in its lower 

 portion highly compact and regularly columnar ; but in passing 

 upwards the columnar structure ceases, and the rock becomes less 

 compact, until at the surface it is a highly vesicular basalt. Di- 

 spersed throughout are crystals of leucite and other volcanic minerals. 

 The castle of Chehrik is built upon a very picturesque rock of the 

 columnar basalt, which is separated from the main mass and stands 

 isolated in the centre of the ravine. The sandstones and gravels 

 exhibit much less change near the overflow of igneous matter than 

 might be expected ; the sandstones, however, are somewhat hardened, 

 and the pebbles appear as though they had been submitted to the 

 action of fire. 



Mixed here and there with the vesicular basalt are amorphous 

 masses of pink, cellular, basaltic scoriae. 



Many of the cells are filled with yellowish carbonate of lime, and 

 contain volcanic crystals, especially olivine and hornblende, with a 

 little mica. Their exterior is more compact than the interior, ex- 

 hibits a greater proportion of calcareous matter, and is frequently 

 coated with a thick enduit of the same. It has been suggested, that 

 these masses are volcanic bombs, but the large size of many of them 

 is opposed to this idea. In my opinion, they are portions of calca- 

 reous tufa, torn from their parent rock during the flow of the basalt 

 over it, and they have assumed their present character by being 

 rolled up and fused in the heated mass, and by the injection of 

 igneous gases. 



In favour of this hypothesis we have on the north side of Anju- 

 lukh Dagh, a very conspicuous peak of stratified travertin, which 

 bears on its summit a famous Castle called Kalah Kami. This 

 peak has been forced up by the granitic rocks of the Dagh, having its 

 strata dipping to the north at an angle of 45°. Its base is concealed 

 under the basalt. The extreme whiteness of this peak forms a striking 

 contrast with the black igneous rock of the adjoining plain. 



* I had no opportunity of visiting the country west of Chehrik, to ascertain 

 the point from which tlie basalt has its origin. At some distance, however, 

 beyond Chehrik, there exists a high peak, with a small extinct volcanic crater, 

 around the base of which Lieut. Glascott, R.N., and Mr Jackson, I.N., observed 

 a vast circuit of basaltic matter. It is not improbable that the basaltic flow over 

 the Plain of Selmas has proceeded from this crater. 



