322 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



church, a part of which was carried away. The back of the building 

 is still nearly two feet in the water. 



Upon the shore of the Lake of Arin lie numerous rounded 

 lumps of volcanic tuff and black scoriae, measuring 6 inches in dia- 

 meter. The tuff is white, with laminae of mica plentifully distributed 

 through it. 



From Horantz the road follows along the basaltic base of Suphan 

 Dagh over pumice-sand. At one or two localities is a conglomerate 

 of volcanic products and white limestone pebbles in a white calca- 

 reous paste. 



About a mile before reaching A'd-el-Jiwaz is a ravine exposing a 

 deep section of gravel, consisting entirely of small rounded pebbles 

 of obsidian and larger ones of white limestone. They loosely adhere 

 together by means of a thin coating of yellow calcareous matter, 

 originating from some extinct travertin spring. This gravel to the 

 west passes into a true volcanic tuff, mixed with carbonate of lime, 

 frequently stalactitic and of open structure, as exhibited at travertin 

 springs. The range to the north of A'd-el-Jiwaz is a convincing proof 

 of the influence which has been at work in depositing the limestone- 

 rocks of this region. This range and the rock on which the Castle 

 stands are nothing more than a travertin deposit on a magnificent 

 scale ; the stone sometimes assuming the character of a true compact 

 yellow limestone*, and at others that of a common precipitate from 

 a spring highly charged with carbonate of lime, and frequently con- 

 taining pieces of reeds. 



On the west of A'd-el-Jiwaz, the road is carried 200 or 300 feet 

 above the level of the Lake, which washes the base of the travertin 

 mountain. The rock is frequently cut in steps for the passage of 

 beasts of burden, and is extremely slippery and dangerous. A narrow 

 irregular alluvial plain, formed by the retiring of the mountains from 

 the Lake towards the north, is then crossed. 



The mountains bear round again to the S.W., and consist of red 

 and blue marls, whose position with regard to the tufa-limestone was 

 not clearly made out, though they appear to overlie it. Further 

 westward, these marls are succeeded by a fine grey volcanic tuff and 

 breccia, with long angular lumps of basaltic lava. 



Beyond the gardens of Siihiir the beds alter their character, pass- 

 ing down into a dusky-red fine-grained tuff, alternating with coarse 

 volcanic breccia, which latter rock obtains as far as Akhlat. 



At several places a more recent conglomerate in a white calcareous 

 matrix rests unconformably in patches on the grey tuff. Here and 

 there are a quantity of loose gravel and numerous lumps of pumice. 

 At Akhlat old town the inhabitants have taken up their abode in 

 holes and chambers excavated in these soft volcanic rocks. Akhlat 

 is celebrated for some fine tombs of the early Mahomedan Princes of 

 the district. The stone used is the red tuff, which is heavier and 

 more durable than the finely-grained grey variety reposing upon it. 

 It is admirably adapted for the delicate and elaborate work which 



* Containing indications of Corals and marine shells. 



