OF GIBRALTAR. 13 



to Grenada, and therefore they must not be sup- 

 posed peculiar to the rock of Gibraltar.. 



The next formation to be noticed is the remark- 

 able osseous breccia, which overlies a great part 

 of the cavern limestone; it is chiefly seen on the 

 east side of the rock, between the fortifications of Cave 

 Guard, and the fishing Bay of La Galetta. As 

 this important breccia formation has been so well 

 described by Spix and Von Martms, I cannot do 

 better than quote here their observations on this 

 interesting subject, more particularly as their work 

 is seldom to be met with. 



" The well-known and remarkable osseous breccia 

 (a limestone breccia), which, towards the sea forms a 

 mantle-shaped cavern, and seems here to dip at an 

 angle of about 30. In some places it fills up the 

 rents, clefts, and corroded hollows in the limestone 

 rock itself. The general cement of this breccia, 

 which is chiefly composed of fragments of the same 

 limestone, is a stalactitic mass of considerable hard- 

 ness, of a reddish brown colour, and full of vesicular 

 cavities, which occur without order, from the size of a 

 poppy-seed, to the extent of several lines. Sometimes 

 it is itself consolidated into reniform pieces, partly 

 rounded, and partly angular, of a smoky gray, and of 

 a light gray limestone, of which the greater part of 

 the Mons Calpe consists ; and it contains kidneys or 

 nodules of a soft, very ferruginous, yellowish brown, 

 fine-grained, calcareous marl, and rounded grains of 

 quartz of the size of a millet seed. Here and there 

 are wavy stripes and streaks of calcareous spar, and in 



