338 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



valley of Kebban, communicated with a similar patch on the 

 opposite side, forming a lode or dyke. The surfaces of the hills, 

 as well here as on the opposite side of the Euphrates, are covered 

 with innumerable rubbish heaps, formed in attempts to open mines 

 which have rarely been pushed more than two or three feet into 

 the ground. The mines at present worked (which are three in 

 number) lie beyond the ridge on the west of the town, and are even 

 more miserably directed than those of Arghaneh. The adit mouths 

 are driven through shale and limestone, which, here and there, 

 shows on the surface small strings and lumps of galena ; but so 

 irregular and dirty are the jvorks, that little can be seen under- 

 ground to inform us how the ore occurs. The lower mine exhibited 

 some rich portions of nearly pure argentiferous sulphuret of lead, 

 but it nowhere had the appearance of occurring in veins, and I 

 could not hear of crystallisations or druses. In the upper mine, a 

 large quantity of soft iron ochre, a sort of gossan mingled with 

 threads of gypsum, is excavated as ore, being found to contain, 

 like the galena, from an ounce to an ounce and a half of silver 

 in 100 lbs. 



The miners told me that near the junction of two species of 

 rock, whether limestone or shale, or of one of these with porphyry, 

 they find the ore more plentifully disseminated than elsewhere. 



Dressing or preparing the ores is not understood, so that all 

 which is not rich enough to go at once to the furnace is wasted. 



Between the Euphrates, at Kebban Maden, and the Kizil Irmak, 

 or Halys, at Siwas, extends a broken and neglected high land, in 

 which the traveller meets with no habitations, except in villages 

 fifteen or twenty miles apart, and these are inhabited by koords of 

 a somewhat lawless character. 



On leaving the felspar porphyry which is found in peaks, or 

 below the sedimentary rocks at Kebban, a high land of limestone 

 and shales is reached. This high land extends up the course of 

 the Western Euphrates, above Eghin, and towards Kamak, where 

 the limestone forms the sides of a magnificent gorge through 

 which the river flows. Superimposed on the older grey limestone, 

 occur beds of a white calcareous rock of softer character, which 

 mineralogically has a strong resemblance to the calcaire grossier, 

 or Grobkalk of the Vienna basin, and contains the shells of oysters. 

 About twelve miles from Kebban, the almost level country is 

 strewed with basalt blocks, like those of the plateau of Diarbekr, 

 which continue beyond the village of Ergavan. An hour's dis- 

 tance from hence, a long valley running up towards the north- 

 east, exhibits porphyries frequently trachytic in character, and 

 containing hornblende crystals in a felspar paste ; and also banks 

 of a conglomerate, containing fragments of the same porphyry. 

 Then, after passing the water shed, about ten miles before reaching 

 Hakim Khan, rise on the right hand precipitous heights of com- 

 pact limestone in beds inclining to the west ; and in some places 

 porphyry comes up from beneath them. The country on the 

 south-west, towards the Euphrates, is composed of low undu- 

 lations of sand and marls. 



