Jan. 23, I860.] BUIST ON THE CURIA MURIA ISLANDS. 53 



" As we approach the centre of Curia Muria Bay on the mainland ** (says 

 Dr. Carter), " a totally different aspect presents itself. Here we observe Ras 

 Shuamiyah, which is about 135 miles from Kas Jazirah, another and much 

 more extensive outbreak of igneous rocks than at the latter point. The former 

 cape consists of a dark-looking mass of igneous rocks, and on either side of it 

 black dykes irregularly extend up through the white strata, in some places 

 raising them and running along between them, in others attaining the summits 

 and flowing along the surface of the cliff, the uniformity of which has been 

 destroyed by the eruption. In some parts it is raised higher than we have 

 hitherto seen it, in others it is more depressed ; a few miles south-west the 

 irregularities still increasing, bring us to a stupendous mass 4000 feet above 

 the level of the sea. Proceeding onwards south-westerly we come to the 

 promontory called Ras Nus, which terminates Curia Muria Bay — a mass of 

 granite rising 1200 feet above the level of the sea." 



Dr. Carter's account of the mainland, here slightly abridged, cor- 

 responds exactly with that of Dr. Hnlton of the Curia Muria rocks. 

 With the exception of the limestone bluff at its northern extremity, 

 Helaniyah consists of a mass of granite penetrated in all directions, 

 and occasionally surmounted, by a dark-coloured rock, which he 

 describes as allied to greenstone, and which, as already stated, I 

 have assumed to be hornblende rock. It occasionally puts on the 

 form of veins or dykes, varying from a few inches to 18 or 20 feet 

 in thickness. Hornblende is described as the prevailing material of 

 which they are composed, mixed to a greater or less degree with 

 felspar — sometimes in a disseminated form, sometimes secreted in 

 crystals forming porphyry. The structure again seems occasionally 

 so to alter that the material of the veins is transformed into some- 

 thing like granite, into which rock it ultimately seems to merge.* 

 The formations throughout the group seem almost perfectly iden- 

 tical, differing merely, and that to a small extent, in the mineralogical 

 character and contour of the rock ; the granite presenting lesser or 

 larger crystals or more or less hornblende in one place than another, 

 the dark rocks varying in like manner, neither in any way chang- 

 ing in any of the essentials of their character. The island of Hela- 

 niyah, where it attains the elevation of 1645 feet above the sea, con- 

 sists of tertiary limestone, abundant in fossils, of what description 

 is not mentioned by Dr. Hulton ; it is shown by Dr. Carter to be 



considers that the rock described by Dr. Hulton is eupotide, which he holds as 

 synonymous with serpentine. 'Geology of Western India/ pp. 569 and 583. 

 Dr. Carter's 'Southern Arabia.' — 'Bombay Asiatic Transactions, 1851.' — 'Geo- 

 graphical Papers of Western India, 1856.' 



* Hulton, slightly abridged. " I am satisfied that more careful examination would 

 show that though the structure of the veins may change its character so as to 

 become closely allied to granite, the veins themselves actually retain their uni- 

 formity." — Letter of Mr. Dawson, late Principal Resident and Superintendent for 

 the Lessees. 



