332 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



racter. Their chief mass is composed of limestones and slates of 

 an older period ; the limestones of a darker colour than that 

 around Arghaneh ; the slate chiefly talcose, and connected with 

 the mica-slates and other primary rocks, described by Russegger 

 as forming the nucleus of the Taurus in the district of Adana. 

 The eruptive rocks, occurring in juxtaposition with these, are 

 syenite, diallage rock, basalt, similar to that of the plateau of 

 Diarbekr, and lastly, at Kebban Maden, a felspar -porphyry. 



Such are the rocks presented in this transverse section of the 

 chain, and the determining of their boundaries is much assisted by 

 the nature of the ground ; for the Taurus is, in this part, so 

 totally bare, that it seldom happens that its geological features 

 are obscured by trees, grass, or even vegetable earth. That 

 forests, however, have once existed, and that at no very distant 

 period, is evident from the oak brushwood which is occasionally 

 met with ; though the inhabitants, in order to supply the furnaces, 

 cut away with unsparing vigour the shoots as fast as they spring 

 up. 



The city of Diarbekr is built on an extensive plain, covered 

 with rough fragments of basalt, resting upon more compact 

 masses of the same rock ; and through these the river Tigris has 

 cut for itself a valley about a hundred feet in depth. On the 

 south of the city, the hills of the Karajah Dagh exhibit varieties 

 of the same rock, which is sometimes amygdaloidal, sometimes 

 scoriaceous. These hills often rise up in strongly marked cones, 

 which bear exactly the type of the ancient secondary cones of 

 Etna ; and are covered by various accumulations, and in some 

 cases overgrown with trees. On the south-west, this igneous 

 formation extends beyond the town of Siverek, a distance of sixty 

 miles from the Tigris ; and in approaching the mountains to the 

 north-west, we find the same series continued for twenty miles. At 

 Arghaneh the southern outposts of the Taurus present their most 

 remarkable features. The celebrated Armenian monastery of this 

 name is built on the summit of a calcareous mountain, which 

 attains a height of 2000 feet above the plain, or 4000 feet above 

 the sea, and is conspicuous from a great distance, owing to its two 

 sharp peaks. Hence we find the place designated in some ojd 

 maps as Arx bicornis. The chief component rock of this and the 

 neighbouring elevations, on the north and east, is a compact light 

 coloured limestone, generally abounding in nummulites, and some- 

 times exhibiting fragments of pecten and ostrea. Against its 

 flanks, on the east and west, rest beds of porphyritic conglomerate, 

 of which the rolled fragments consist chiefly of greenstones with 

 imbedded large crystals of hornblende. The stratification of the 

 limestone is not very distinct at this spot ; but, on the road to the 

 north-west, the beds become remarkable, being exhibited in long 

 denuded parallel lines, generally tilted from the southward. The 

 limestone is accompanied by slates of a highly metamorphic cha- 

 racter : they are black, grey, ferruginous, or green in colour ; and 

 from beneath them there appears a greenstone porphyry, which, 



