Mr. De la Beche on the Geology of Jamaica. 145 



an opportunity of observing whether or not the same causes have been in 

 action in various parts of the earth's surface; and whether the superposition 

 remarked in one portion of the globe, is the same with that seen in another. 

 He moreover will see whether or not rocks exist, which are not included in 

 our European lists : for as we sometimes find several formations wanting be- 

 tween two rocks in England and elsewhere, so may we find rock formations 

 in America which are wanting in Europe ; there being no more reason why in 

 a series of rocks, represented by a, ^, y, §, § should not be missing in Europe, 

 than that /3 should be found in England and be wanting in Germany. 



The following observations will be confined to that part of Jamaica which is 

 situated to the eastward of a line drawn from Alligator Pond Bay to St. Ann's 

 Bay, thus taking in nearly the eastern half of the island where the most ele- 

 vated mountains are found. The whole of this portion of Jamaica is hilly and 

 mountainous, with the exception of the extensive plains of Liguanea, St. 

 Catherine's, St. Dorothy, Vere, and the lower part of Clarendon. 



The highest range in the island is that of the Blue Mountains, situated in 

 the eastern part of Jamaica, in the parishes of Port Royal, St. David, St. 

 Thomas-in-the-East, Portland, and St. George. Their principal direction is 

 nearly east and west ; but they do not, as is often represented, extend through 

 the whole length of the island : for with the other mountains to the westward 

 of the Agua Alta, or Wag Water, they have no connexion. The Cold or 

 Main Ridge varies from about 5,000 to 6,500 feet in height, and the summit 

 is in some places so narrow as not to be more than three or four yards across. 

 From the northern side of part of this ridge, a curved ridge detaches itself, of 

 greater elevation than the other; and from this curved ridge rise three principal 

 masses, which have obtained the name of peaks, that to the east being the 

 most conical. Robertson, in his map of Jamaica, estimates their different 

 heights, at 8184, 7656, and 7576 feet above the level of the sea, that which he 

 calls the northern peak being the most elevated. These heights 1 am in- 

 clined to think too great ; for my barometrical measurements, though incom- 

 plete, would seem to give about 7600 feet for the highest peak *. 



Catherine's Peak, which I found by barometrical measurement to be 4971 

 feet in height, forms the highest point of the mountains crossing the island 

 from N.W. to S.E. through the parishes of Port Royal, St. Andrew, and St. 

 George, and constituting the next highest range to the Blue Mountains. 

 The Port Royal mountains are of considerable elevation even near the sea, 



* My barometer was broken and rendered useless upon the ridge from whence the peak rose ; 

 but it had previously given me 7163 feet for the height of the ridge, and I do not think that the 

 summit of the peak was more than 400 or 300 feet above it. 



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