1824,] the Rocks of Mount Sorrel, far, 5 



opportunity for studying its nature. Some rocks, however, 

 appear in situ on an eminence between the town and Buddon's 

 Wood ; while some also overtop the surface of Rothley Plain, 

 of which the gradual descent begins at the abovementioned 

 quarry, called Simpson's Pit ; and in the earlier part of the 

 descent of this plain, rocks perfectly resembling those of Mount 

 Sorrel occasionally overtop the general surface, sinking, as has 

 already been observed, ultimately beneath it, and so completely 

 that it is impossible to discover their connexion with those of 

 the Forest. 



The aspect of the Mount Sorrel rock is granitic, and hand 

 specimens may, perhaps, be found, of which the ingredients 

 appear to be confined to those commonly considered as being 

 essential to granite ; namely, quartz, felspar, and mica; for the 

 hornblende which generally is sufficiently apparent, and which 

 often abounds, is occasionally so nearly wanting, or so minute 

 in small specimens, that it may easily be overlooked. In reality, 

 however, much of that which appears to be felspar, is not that 

 mineral, but cleavelandjte. Epidote occasionally enters into its 

 composition, but is more generally found in small nests or veins, 

 with semi-transparent quartz, when it is sometimes associated 

 with magnesian carbonate of lime, which cleaves into rhom- 

 boids, and slowly effervesces, in diluted muriatic acid ; silvery 

 talc appears sometimes on the quartz found in veins or nests in 

 the rock, and the same substance of various colours enters into 

 the composition of some of those which overtop the grassy slope 

 of Rothley Plain. Chlorite also in small quantity is sometimes 

 diffused through the mass, and occasionally appears traversing 

 it in thin irregular veins. 



The quartz entering into the composition of this rock is 

 transparent or semitransparent, the mica in thin hexagonal 

 plates, and the surfaces produced by dividing them parallel to 

 the terminal plane are very splendent and of a colour nearly 

 approaching to black, but by transmitted light the laminse appear 

 of a dingy-brown. The hornblende is of a dark bottle-green, 

 approaching to black. The felspar and cleavelandite, which are 

 almost constantly the prevailing substances, vary greatly in 

 colour, are intermingled in the mass, and cannot always be dis- 

 tinguished from each other by their external characters. Both 

 are commonly red or reddish, and this colour is sometimes so 

 powerful in the cleavelandite as to impart to it the aspect of red 

 jasper, particularly whenever it assumes in any degree the 

 appearance of a vein ; the planes produced by fracture are then 

 generally curvilinear, and without lustre. Sometimes, however, 

 the felspar and cleavelandite are intermixed, either simply, or in 

 such a manner as to impart to the rock a porphyritic character ; 

 the felspar is generally translucent, and the imbedded cleave- 

 landite white and nearly opaque, and the other ingredients of 

 the rock then form a small grained paste. We were not in the 



