464 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [June 21, 



I shall leave, therefore, to future inquiry the solution of the interest- 

 ing problem of the natural affinities of these wonderful bipedal forms, 

 contented if I have fortunately been instrumental in placing their 

 significant memorials in the catalogue of Palaeontology. 



3. On the Geology of portions of the Turko-Persian Fron- 

 tier, and of the Districts adjoining. By William Kennett 

 Loftus, Esq., F.G.S, 

 [Communicated by the Foreign Office, by order of the Earl of Clarendon.] 

 [Abstract.] 



The geological researches detailed in this memoir were made in the 

 years 1849-52, during the progress of a joint commission appointed 

 by the English, Russian, Turkish, and Persian governments for the 

 demarcation of the Turko-Persian frontier. 



The line of country investigated during the Sun^ey bears in a 

 N.N.W. direction from Mohammerah, at the head of the Persian 

 Gulf (Lat. 30° 26' N.), to Mount Ararat (Lat. 39° 42' N.) ; a 

 direct distance of rather more than 600 geographical miles. 



The first 2.50 miles, from Mohammerah to near Mendali, is an 

 arid and deserted waste, infested by plundering parties of Arabs and 

 Kurds, but capable for the most part of extensive cultivation. 



From Mendali to Zohab (50 miles) the exterior tertiary chain of 

 low gypsiferous ridges, which everywhere skirt the west flank of the 

 Zagros, is crossed ; and at the latter place the nummuhtic limestone 

 and cretaceous rocks are first reached. 



From this point to near the Lake Zerribar (60 miles) is a succes- 

 sion of regular, saddle-formed, limestone antichnals, with alternate 

 synchnals, containing disconnected portions of the gj^psum series, 

 and underlaid by older blue schists. 



The remainder of the frontier exhibits a lofty range composed of 

 igneous rocks, which, bursting through the stratified deposits, con- 

 stitutes the axis of the vast barrier ridge nearly as far as Bayazid, at 

 the south foot of Mount Ararat, a distance of 2/0 miles. 



Other traverses were made as far south as Shiraz (Lat. 29° 36' N.), 

 and many valuable sections obtained, which are referred to in the 

 memoir. 



In the first place the author gives a general section across the 

 great Zagros range, as illustrative of the general arrangement of the 

 rocks in the southern district. Thus the plain of the Tigris and 

 Euphrates consists of red sandstone and variegated marls, bordered 

 by hills of conglomerate, which are succeeded by higher hills of the 

 same, capped by gypsum and miderlaid by nummulitic rock. The 

 latter forms still higher escarpments to the eastward, which are also 

 surmounted by disturbed gypsum beds, and are based on cretaceous 

 rocks. These in their turn crop out beyond the nummulitic rocks 

 on the high lands eastward, and are succeeded by a crystalline lime- 

 stone, obscure in its relations ; and this by clay slates and mica 

 schists, which are perforated by the granitic axis of the chain. 



