GEOLOGY. 351 



nothinor which he had not examined with the greatest care. 

 These fracrments were afterward reduced to order by Nie- 

 buhr, according to the Linnaean arrangement, and published 

 in Latin in two quarto volumes.* Owing to the rigour with 

 which Christians were then excluded from the Holy Land of 

 the Moslem, the observations of the Danish travellers were 

 necessarily restricted to the southern provinces, and those 

 parts of the country thro'igh which Niebuhr passed in his jour- 

 ney from Bagdad to Aleppo. Since that time Mohammedan 

 bigotry has relaxed ; but this tolerance has not much in- 

 creased the information of naturalists ; and a few geological 

 remarks gleaned from the pages of Burckhardt and Ali Bey 

 are all that have been added to the scientific treasures of the 

 northern philosophers. In collecting and arranging the ma- 

 terials which we have drawn from these various sources, we 

 have been less anxious to follow a particular system than to 

 present the general reader with a simple and intelligible trea- 

 tise on the subject. 



SECTIOX I. GEOLOGY. 



Mountains. — It has been already stated in the description 

 of Arabia, that the mountain-chain which traverses that 

 peninsula from north to south is a continuation of Lebanon in 

 Palestine. Passing eastward of the Dead Sea, it runs to- 

 wards Akaba, and from thence extends as far as Yemen ; in 

 some places approaching the shore of the Arabian Gulf, and 

 in others being separated from it by the intervening plain of 

 Tehama. On the eastern side the descent of this range is 

 less by one-third than on the western, owing perhaps to the 

 constant accumulation of sand ; so that the great central 

 desert is considerably elevated above the level of the sea. The 

 lofty summits, that tower to the clouds when viewed from the 

 coast, dwindle into mere hills when seen from the interior. 

 At Wady Arabah the surface of the western plain is perhaps 

 1000 feet lower than the eastern. The structure of Gebel 

 Shera (Mount Seir) is principally of calcareous rock ; there 

 are also detached pieces of basalt, and large tracts of breccia, 

 formed of sand and flint. About Mount Hor and Wady 

 Mousa sandstone of a reddish colour prevails ; and from this 



* Flora Arabica, 4to Hafniae, 1775. Descriptiones Anima« 

 iiura, ibid. 1775. 



