Maculla Hot Spring in Arabia. 33 



the evidence of our countryman Mr Wollf, the Abyssinian tra- 

 veller and missionary, who, in his travels to Senaar in Febru- 

 ary last, mentioned to me that he was told an active volcano at 

 present existed about four days' journey from this very spot. 

 The assertion, of course, originating with an Arab, is not to be 

 hastily adopted ; but, nevertheless, it would not be surprising, 

 taking collateral circumstances into consideration. Moreover, 

 were not this the case, that is, their occurrence in an otherwise 

 non-volcanic district, it is well known that some also are asso- 

 ciated with granite and other rocks, to which most assign an 

 igneous origin, and consequently the same causes produce 

 similar effects. An excellent example of such is to be found 

 in the upper part of the Jumna, in the now Agra Presidency, 

 where the springs issue from rocks of granite with a tempe- 

 rature of 1 94° F., and other similar instances in the same and 



may not be trespassing too far to take notice of here, that is, that in Lat. 18", 

 on the east coast of the Red Sea, there is at present a coral rock 120 feet 

 above the surface, the very summit of which, and the greater part of the 

 side, is crowned by corals upon a volcanic foundation, which one would cer- 

 tainly imagine, and not incorrectly, must have been raised by some eruption 

 whilst the process of incrustation by these animals was going on, — an evidence, 

 moreover, which perfectly sides with the previous hypothesis, that almost all 

 the coral rocks in this sea are formed upon a similar basis. This, I am aware, 

 is objected to by many, who are of opinion that the alternate rising and falling 

 of the sea is amply sufficient to account for such an occurrence. 



Now, this rising and falling of the sea cannot, in this case, account for the 

 phenomenon in question, since in no quarter of the globe are we aware of 

 the tide rising to a height exceeding 100 feet, viz. in the Bay of Fundy, and 

 even this is doubtful; and here the highest is never known to reach one-half 

 of the above. 



From this, therefore, we might almost come to the conclusion, that what 

 are denominated coral rocks here, and perhaps even in other parts of the 

 globe, are in fact nothing more than the remains of extinct volcanoes, or 

 other rocks incrusted by these animals, and by degrees raised to their present 

 height, a summary which might probably be resolved into the four following 

 stages, viz. Volcanic rocks naked and above the surface of the sea ; the same 

 naked above the surface, incrusted with coral below ; thirdly, incrustations 

 below the surface, upon a supposed volcanic basis ; and, fourthly. Volcanic 

 rocks with coral incrustations above the surface. 



It ma)' be stated, that, for the fact above alluded to with regard to 

 the soundings, I am indebted to the kindness of Lieutenant Campbell of 

 H. E. I. C. S. 



VOL. XXIV. NO. XLVII. .lAigUAUY 1838 C 



