LOFTUS TURKO-PERSIAN FRONTIER. 311 



The travertin is so largely developed, and is so intimately con- 

 nected with the marls, that there can be little doubt of their being 

 chiefly composed of it. The presence of iron has of course produced 

 their variegated colours ; and it is a coincidence, that the travertin 

 deposits, v^^hich are at the present day forming at innumerable places 

 in the ravine, derive their colours from the quantity of iron held in 

 solution by the springs. 



From the vast extent of the travertin deposits in this region, — 

 and, in many instances (when acted upon by igneous eruptions, as in 

 the ravine of the Kotur stream, and at Derik), from their remarkable 

 similitude to the nummulitic limestone of the south, — I am inclined 

 to think that they have had considerable share in the formation of 

 the earliest tertiary rocks of the Frontier. 



It is remarkable that some of the friable limestone of Giiverjin 

 Kalah, — and of the No. 7 bed of the Kirrind and Mahidesht section 

 (fig. 9, zg), p. 2/6, Part I. of this paper, — cannot be distinguished 

 from the altered travertin of Derik, &c. Supposing that the seas of 

 the Nummulitic period abounded in travertin springs, would not the 

 superabundance of calcareous matter sufficiently account for the 

 extreme rarity of animal life, and hence of fossil remains ? 



At twelve miles from the Beacon, the small valley of Zerri 

 branches off on the right bank of the stream. Here the variegated 

 marls entirely cease, and are succeeded by a second eruption of 

 igneous rocks ; — viz. the same fine-grained green granite as before, 

 traversed by veins of carbonate of lime, — a dark-coloured serpentine, 

 — and a grey conglomerate of felspar and talc rock. The ravine now 

 widens, and gradually expands into the pretty Plain of Kotur, which 

 is bounded on the east and south by igneous rocks. 



On quitting the Plain of Kotur, the road turns to the N.W., and 

 passes through a series of red altered sandstones, containing thick 

 beds of gravel-conglomerate, and resting upon a hard chert-rock, of 

 pinkish-grey colour, which is frequently traversed by veins of a 

 beautiful red felspar with talc. 



It is not improbable, that the upper layers of gravel are identical 

 in age with those so much altered and resting on the granite in the 

 ravine between Khoi and Kotiir ; and they possibly belong to the 

 gypsiferous formation. 



Turning towards the north, the chert-rock overlies compact blue 

 limestone, in thin layers. 



All the above beds are elevated and thrown downwards to the 

 south, at an angle of 45°, by the mountain of Hallep Dagh, which 

 is chiefly composed of very dark-green serpentine and fine-grained 

 grey granite. Thin veins of light-green steatite traverse the ser- 

 pentine. In one locality the serpentine mass overlies the blue lime- 

 stone, which is at the point of junction much contorted. 



At the top of the Pass between Kotur and Sherab Khaneh is a 

 little freshwater lake, surrounded on all sides by small peaks and 

 undulations of limestone. 



From Sherab Khaneh the road crosses a low limestone-ridge, 

 covered with fine loose gravel, and descends into the somewhat lower 



