IX. A Short Mineralogical Description of the Moun- 

 tain o/Gibraltar. By Major IMRIE. Conwmnicated 

 by the Reverend JOHN WALKER, D. D. ProfeJJbr of Na- 

 tural Hijiory in the Univerfity of Edinburgh, 



iReadJuly 2,. 1797.] 



THE mountain of Gibraltar is fituated in i^". g north lati- 

 tude, and in 5°. 17' eaft longitude from Greenwich. It is 

 the promontory which, with that of Ceuta upon the oppofite 

 coaft of Barbary, forms the entrance of the Straits of Gibraltar 

 from the Mediterranean ; and Europa Point, which is the part 

 of the mountain that advances moft towards Africa, is generally 

 regarded as the moft fouthern promontory in Europe. The 

 form of this mountain is oblong ; its fummit a Iharp craggy 

 ridge ; its diredion is nearly from north to fouth ; and its 

 greateft length, in that diredlion, falls very little fhort of three 

 miles. Its breadth varies with the indentations of the fhore, 

 but it no where exceeds three quarters of a mile. The line of 

 its -ridge is undulated, and the two extremes are fomewhat high- 

 er than its centre. 



The fummit of the Sugar Loaf, which is the point of its 

 greateft elevation towards the fouth, is 1439 ^^^'^ 5 ^^^ Rock 

 Mortar, which is the higheft point to the north, is 1350 ; and 

 the Signal Houfe, which is nearly the central point between 

 thefe two, is 1276 feet above the level of the fea. The weftern 



fide 



