LOFTUS TURKO-PERSIAN FRONTIER. 251 



mentioned locality, at Gerah on the Euphrates ; and Messrs. Fraser 

 and Ross, during a journey through the Jezireh of Chaldaea, observed 

 a large surface of the desert on the banks of the Shat el-Hie, a few 

 miles to the N.E. of Worka, literally composed of shells. It is to be 

 regretted that none were preserved. 



Still further to the north, in the centre of the Jezireh, in about 

 lat. 32° 10' N., between the Lemliim marshes and the ruins of Niffr, 

 I picked up numerous pieces of silicified shell-conglomerate with a 

 white and siliceo-calcareous matrix. From the abundance of these 

 fragments, and from their angular aspect, it is evident that they 

 must have been derived from the immediate locality, although the 

 outcrop and position of the beds, with relation to the older and 

 newer deposits, are entirely concealed beneath the drifted sands of 

 the desert. 



Mr. Ainsworth, who had good opportunities for examining the 

 order of stratification of these beds, exposed in the sections upon the 

 banks of the Euphrates, divides this marine formation into two parts : 

 — *' the upper and more sandy beds were characterized by the tro- 

 choidal and buccinoidal forms of turrited univalves ;" and the most 

 abundant shells in the lower argillaceous beds were a Venus, a Cyrenay 

 a Mytilaceous shell, and some turrited univalves. {Op. cit. p. 123.) 



An examination of the fossils of this marine deposit proves, that at 

 a comparatively recent period the littoral margin of the Persian Gulf 

 extended certainly 250 miles further to the N.W. than the present 

 embouchure of the Shat-el-Arab — the combined stream of the Tigris 

 and Euphrates, and 1 50 miles beyond the junction of these two great 

 rivers at Korna. 



The actual extent of this marine deposit to the N.W. it is im- 

 possible to define, as, from the nature of its formation in the shallow 

 estuary, it probably passes upwards gradually into the more recent 

 fluviatile beds. 



Mr. Ainsworth, in his * Researches,' and Col. Rawlinson, in a paper 

 read before the Geographical Society in 1850, have both shown the 

 rapid accumulation of this alluvial deposit, which is represented to 

 increase a mile in thirty years at the head of the Persian Gulf. It 

 is therefore needless here to repeat the investigation ; — especially as 

 I have no new matter to add upon the subject. 



2. Lacustrine Deposit. — The only deposit of this nature which I 

 was so fortunate as to meet with was in the mountains of Luristan, 

 upon the elevated plateau of Hassan-i-Gowdar, between Khorremabad 

 and Bisiitun. This plateau is surrounded on all sides by lofty peaks, 

 and presents the appearance of having been at some time or other 

 the basin of a lake. A small stream on the north side of the plain 

 exposed a section 1 2 feet deep, and exhibited a friable, loose, yellowish 

 limestone, filled with freshwater shells, viz. — 



Planorbis ; allied to P. corneus. 

 Planorbis ; a striated species. 

 Planorbis ; allied to P. marginatus , 

 Lymnaeus ; an elongated species. 



