284 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



tact with igneous rocks near the central axis as to render their deter- 

 mination during rapid traveUing quite out of the question. 



In the upper part of the Secondary Rocks of the Zagros some 

 portion of the Cretaceous Series is certainly represented, but where 

 to draw the line of its basement is not easily determined. 



In one locality the blue schists of this formation appear, however, 

 to pass downwards imperceptibly into the crystalline blue limestone 

 which constitutes the eastern portion of the mountain ranges on the 

 Frontier. 



1 . Upper Secondary or Cretaceous Series. 



In describing the Nummulitic Series, I have already referred to a 

 few sections in which the beds of the Cretaceous age are apparently 

 overlaid conform.ably by those older Tertiary Rocks. 



Along the Frontier no sections fell under my observation which 

 were sufficiently well developed to place this fact beyond a doubt ; 

 and it was only in the interior of the Bakhtiyari Mountains that I 

 was fortunate enough to satisfy myself completely on the subject. 



Section (fig. 11) from Mdl A' mi to Ser Khicn, Bakhtiyari Moun- 

 tains. — This section is on the direct road between Kalah Tiil and 

 Isfahan. 



The crystalline (cretaceous) limestone forming the range of Kil- 

 gird having been crossed from the plain of Mal-A'mir by the Rah-i- 

 Siiltan, the Kuran River is reached in a narrow valley, flowing through 

 a gravel- deposit which rests in a trough of the gypsum-series. On 

 quitting the river the road is carried by a steep ascent up the prettily 

 wooded ravine of Rikat over reddish-yellow sandstones, blue and red 

 marls, and gypsum, in the same order of succession as elsewhere ob- 

 served ; the dip being slightly towards the Kiiran, but a good deal 

 disturbed. From the head of the ravine an undulating plain of con- 

 torted sandstones and marls, well-wooded, is crossed to the village of 

 Deh-i-Diz, at the foot of the Mush Kuh. The western side of the 

 range is composed of indurated cream-coloured clunch, without fos- 

 sils, which, after the first steep ascent from Deh-i-Diz, forms an 

 excellent road to the summit. This rock dips at a great angle to 

 the west, adapting itself to the saddle-shaped curve of the central 

 mass. Near the summit, however, the clunch ceases, and the under- 

 lying rock appears from beneath it, — at first having the same westerly 

 inclination, but gradually at the summit curving over, until it dips at 

 an angle of 45° in the opposite direction. This rock (fig. 11, 4 c) 

 is a hard, light-grey, and indurated limestone, belonging, I conceive, 

 to the Upper Chalk, since I found in it a fragment of a Sphserulite*. 

 After a descent of several hundred feet, this limestone is overlaid by 

 fissile blue shales and indurated marl (4 b) having the same dip. 



The Mewari Pass is next crossed, in the ascent of which the lime- 

 stone beds (4 «) occur in ascending order. 



* For remarks on Radiolites (Sphceruliies) in general, and for a notice of tlie 

 specimens of Hippurites which Mr. Loftus brought from the East, see Mr. Wood- 

 ward's Memoir, Quart. Journ. Gaol. Soc. No. 41, Feb. 1855. The locahty for the 

 Asiatic Hippurites there described should have been Hakim Khan in Turkey in 

 Asia, instead of the Bakhtiyari Mountains. — Ed. 



