'1 96 Minerahg'ical Defcr'iption of Gibraltar. 



ground that leads to the jilhrnus, and is entirely covered with fortification. The eaftern 

 fide of the mountain raoftly confifts of .a range of precipices j but a bank of fand rifing from 

 the Mediterranean in a rapid acclivity covers a thii:d of its perpendicular height. Its 

 fouthern extremity falls in a rapid flope from the fuinmit of the Sagai-loaf into a rocky flat 

 of confu'erable extent called Windmill-hill. This, flat forms half an oval, and is bounded by 

 a ifange of precipices, at the fouthe^in bafe of which a fccond rocky fiat takes place fimilar in 

 form and extent to Windmill-hill ; and alfo like it furrounded by a precipice, the fouthern 

 extremity of which is waflied by the fea, and forms Kuropa Point, Upon the weflern fide 

 this peninfular mountain is bounded by the bay of Gibraltar, which is in length nearly eight 

 miles and a half, and in breadth upwards of five milef. In this bay the tide frequently rif.:s 

 ■ four feet. Upon the rforth the mountain is attached to Spain by a low fandy ifthmus, the 

 grcatcft elevation of which above the level of the fea does not exceed ten feet, and its 

 breadth at the bafe of the rock is not more than three quarters of a mile. This ifthmus 

 fcpaiatcs the Mediterranean on the eaft from the bay of Gibraltar on the weft. 



This mountain is tnuch more curious in its botanical than in its mineralogical productions. 

 In refpe£l to the firft, it conne£ls in fome degree the Flora of Africa with that of Europe. 

 In refpeft to the latter, it produces little variety ; perhaps, a few fubftances and phenomena 

 that are rare, but none that are peculiar. 



The principal mafs of the mountain rock confifts of a grey denfe (what is generally called 

 primary) marble; the different beds of which are to be examined in a face of 1350 feet of 

 perpendicular height, which it prefents to Spain in a conical form. Thefe beds or ftrata 

 are of various thicknefs, from 20 to upwards of 40 feet, dipping in a dire£lion from eaft t* 

 weft nearly at an angle of 35 degrees. In fome parts of the folid mafs of this rock I have 

 found teftaceous bodies entirely tranfmuted into the conftituent matter of the rock, and their 

 interior hollows filled up with calcareous fpar ; but thefe do not occur often in its compofi- 

 tion, and its beds are not fcparated by any intermediate ftrata. 



In all parts of the globe where this fpecies of rock conftitutes large diftri£ls, it is found 

 to be cavernous. The caves of Gibraltar are many, and fome of them of great extent. 

 That which moft deferves attention and examination is called St. Michael's Cave, which is 

 fituated upon the fouthern part of the mountain, almoft equally diftant from the Signal-tower 

 and the Sugar-loaf Its entrance is loco feet above the level of the fea : this entrance is 

 formed by a rapid flope of earth which has fallen into it at various periods, and which leads 

 to a fpacious hall incrufted with fpar, and apparently fupported in the centre by a large mafly 

 ftalaftitical pillar. To this fucceeds a long feries of caves of difficult accef^. The paffages 

 •from the one to the other of thefe are over precipices, which can only be pafted by the aflift- 

 ance of ropes and fcaling-ladders. I have myfelf pafted over many of thefe to the depth of 

 300 feet frorn the upper cave j but at that depth the fmoke of our torches became fo difagree- 

 able that we were obliged to give up our purfuit, and leave caves ftill under us unexamined. 

 In thefe cavernous recefles, the formation and procefs of ftaladlites is to be traced from the 

 fiimfy quilt-like cone, fufpended from the roof, to tiie robuft trunk of a pillar, three feet in 

 diameter, which rifes from the floor, and feems intended by nature to fupport the roof from 

 which it originated. 



The variety of form which this matter takes in its different fituations and direflions renders 

 this fubterraneous fcenery ftrikijigly grotefque, and in fome places beautifully picfturefque. 



The 



