310 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



Section between the Plain of Khoi and Van. Fig. 19. 



From the Plain of Khoi the road to Kotiir traverses a long narrow 

 ravine up the course of the small stream, flowing from Kotur to 

 Khoi. The precipitous mountains on either side are variegated with 

 every hue and shade of contorted calcareous marls or limestones ; but 

 the beds are' utterly devoid of fossils, — undergo every degree of con- 

 tortion, — and graduate insensibly into each other in colour, so that it 

 is quite impossible to make out any regular order of stratification. 



For the first two miles from the entrance of the ravine, the varie- 

 gated marls occur on both sides ; but at the Beacon, erected by H. E. 

 Dervish Pasha, the Turkish Commissioner, the following descending 

 section was observed : — 



1 . Dark-brown heavy ironstone-clay. 



2. Light-blue or grey calcareous slates, varying through inter- 



mediate shades to dark-purple ; of great extent, frequently in 

 a decomposing state. 



3. Highly indurated, deep-red, calcareous marls and clay slate, 



sometimes passing into serpentine ; and compact limestone 

 enclosing amygdaloid. 



4. Compact limestone, varying from light-grey to dark-olive- 



green, containing small crystals of carbonate of lime. 



About four miles from the Beacon is a solitary flat-roofed Caravan- 

 serai, close to which is a chalybeate spring, ^7° Fahr., depositing 

 calcareous tufa as at Derik. Above the spring is an horizontal bed 

 of gravel-conglomerate, resting against the curved strata of red 

 indurated marls. The extent to which tufa- deposits have taken 

 place during the formation of the marls is very remarkable. The 

 tufaceous layers are intercalated between, and partake of the con- 

 tortions of, the various beds of marls ; while they have all under- 

 gone similar changes from the action of heat. The tufa varies from 

 the loose and friable state of its first deposition to a compact lime- 

 stone, and even to yellow or white saccharoidal marble. 



At seven miles from the Beacon is an eruption of igneous rocks, 

 where the following interesting section occurs : — 



3. Variegated and highly calcareous marls, with much travertin, 

 in layers and in mass. Some of these marls or limestones 

 eff'ervesce yellowish-green with muriatic acid. 



5. A thick bed of gravel-conglomerate ; the pebbles are cemented 



in brown oxide of iron, and are converted into hard dark- 

 green or black chert by the action of the underlying igneous 

 rocks, — which consist of : — 



6. {a) pinkish trap, containing much leucite and hexagonal 



prisms of mica ; 

 {b) finely grained greenish granite. 

 The travertin has been abmidantly deposited during the formation 

 of the gravel-conglomerate, as well as during the igneous eruption ; 

 since it occurs in a much altered state in the midst of the gravel, as 

 well as between the gravel and granite, whicji it likewise traverses in 

 broad highly crystallized veins. 



