360 Geological Specimens from the Persian Gulf. [Xo. 4, 



cross over its seaward margin, and at 70 miles from the last mention- 

 ed island, arrive at those of Zirk&h, Daus, and Jirnain, after which, 

 a few miles west, come the islands of Arzenie, Daeny, and Dalmy, 

 which latter lie respectively, N.W. and S. W. of the former. 



The island of Zirkiih, which rises 540 feet ahove the level of the 

 sea, and is by far the highest in the two groups, presents not merely 

 remnants, but an exact geological type of the islands on the Persian 

 side, viz. volcanic rock capped with " Milliolite,"* together with 

 altered shale and specular iron-ore. 



Of the same type, also are Daus and Jirnain, but toitliout the Milli- 

 olite. 



In the next group, the island of Dalmy, which is 244 feet in its 

 highest part, and only 25 miles from the Arabian coast, we find again 

 the same kind of volcanic and marine formations ; thus carrying them 

 on to within a few miles of the mainland, on which there are no doubt 

 points, here and there, where they might be equally well verified, and 

 thus completely extended from one side to the other, of the lower 

 part of the Persian Gulf. Some of the specimens of " peacock-iron- 

 ore" from Dalmy are as beautiful as any that I have ever seen from 

 the island of Elba. 



The island of Arzenie is also composed of volcanic rock capped with 

 Milliolite, while that of Daeny which is only 9 feet above the water, 

 consists of compact limestone altered by heat and also capped with 

 Milliolite, shewing at once the kind of strata through which the 

 volcanic rock has been thrown up and that which has subsequently 

 been deposited on it. 



Lastly the little island of Hawlool, which is outside the " Great 

 Pearl Bank," 180 feet high, and 45 miles north of the last mentioned, 

 is again composed of volcanic rock capped with Milliolite, while the 

 island of Yassart, which lies nearly south of the latter and within ten 

 miles of the Arabian coast, presents the Milliolite alone, and thus, as 

 far as our observations extend, disappears the volcanic rock from the 

 southern-most part of the Persian Gulf. 



Doubtless there are points, as before stated, on the mainland, here 

 and there, where the volcanic rock projects above the surface, but 



* For a description of this type and the " Milliolite," see uiy first " Report" 

 loc cit. 



