218 E. HILL AND T. G. BONNEr ON ME 



way, and the felspar also, except that it is rather more pellucid 

 than in the last. There has been some orthoclase, but most of the 

 crystals, judging by their form and remains of twinning, have been 

 plagioclase. This change, however, towards the exterior of a mass 

 is not unusual ; still if any one confined his examination to the 

 slides, he might have a little difficulty in believing them to be from 

 the same boss of rock. A few traces of the graphic structure may 

 be observed. The iron peroxide here has more the appearance in 

 decomposition of magnetite, but it is not very characteristic. 



Hence this group of rocks may also be classed with the Syenites, 

 though approaching yet a little nearer than the others to the Diorites ; 

 and, as already stated, we consider them, both physically and litho- 

 logically, as forming a single series. 



(4) Homblendic Granite of the Quorndon District. — The rock 

 occurs as an insulated mass near the eastern edge of the Keuper, 

 dominating the left bank of the Soar valley. The principal portion 

 of it forms the great tree- clad hill called Buddon "Wood, from which 

 a large spur runs out to the east, terminating at the village of 

 Mount Sorrel, in the noted hill of the same name. There is an 

 outlying patch crossed by the Loughborough Eoad on the N.E., and 

 two in a line to the S.W., that of Kinchley Hill and the small knoll 

 in Brazil Wood. All these are probably connected beneath the 

 Trias in the same way as the southern syenites, though the last- 

 named patch is more isolated than the rest. About 100 yards to 

 the S.S.W. of this the unique gneiss of Brazil Wood (p. 783) forms 

 a knoll. This is the only indication of the limit of the massif, what 

 is now visible being simply the tops of granite hills rising above 

 the encircling Trias as from a sea*. Besides the extensive quarries 

 of Mount Sorrel, smaller quarries exist near Quorndon and else- 

 where, and the rock is generally easily examined, except in part of 

 Buddon Wood, where it is overgrown by vegetation. The normal 

 rock is a not very coarse, pinkish granite, S. G. 2-65 (Ansted), con- 

 sisting of quartz, felspar, black mica, and dull green hornblende, 

 with occasional pyrite and epidote. In the Mount- Sorrel pit there 

 is also a greyer variety in which the pink tinge is almost absent from 

 the felspar. As in the syenite, so here, there appears to be no law 

 regulating the occurrence of these varieties. Infiltration or contem- 

 poraneous veins of a pink felsitic rock are common in places ; and 

 there are some dykes to be presently described. 



The granite is occasionally slightly porphyritic in structure, the 



* The Mount-Sorrel pits show excellent sections of the Keuper, containing 

 granite boulders at the base, resting on a very irregular surface of granite. 

 This, near the entrance of the pit, is known to descend for many yards almost 

 vertically. Considerable difficulty was found in completing the foundations of 

 a crane, one side of which rested in the live rock. A well at the engine-house 

 about 100 yards from this has been sunk in the Keuper to 100 feet without 

 reaching the granite. On the edge of the upper part of the hill is boulder-clay 

 resting apparently in a valley scooped out of the Keuper. The rock above 

 seemed to bear (in 1873) faint indications of glacial action on its generally 

 roughened pi'ominences. Mr. W. J. Harrison, in his useful book ' Geology of 

 Leicestershire,' gives a good account of the Forest drift and a photograph of 

 the granite rock. 



