54 PEOCEEDIKGS OF THE GEOLOGICAL SOCIETT. 



of the range, there is every possible intermediate form. The schistose 

 hornblendic rocks are for the most part deficient in quartz, although 

 slaty hornblende and quartz rock occurs in the hollow north of 

 the hill overlooking Brand Lodge, and on the western slope of the 

 Worcestershire Beacon. Per the most part, however, they are 

 hornblende and felspar schists, or slaty hornblende rocks. In some 

 of the thick-bedded and finer-grained hornblendic rocks of the 

 northern part of the range, qtiartz or mica, or both, are sometimes 

 added to the felspar and hornblende ; but these additions are local, 

 and by no means characterize the rock. 



This variability in mineral composition, and the occasional presence 

 of quartz, distinguish the metamorphic from the erupted diorite, 

 and are quite consistent with its probable origin from argillaceous 

 deposits. It is not improbable, also, that some of these metamorphic 

 hornblendic rocks may be lava-beds that were interstratified with 

 the other sedimentary deposits of the epoch, and that have been 

 altered by the same influences. 



The gneissic rocks which make up the larger portion of the range 

 are for the most part thinly bedded, and often highly foliated, espe- 

 cially the finer-grained varieties which occur at the northern end of 

 Midsummer Hill, the southern half of Swinyards Hill, and between 

 the Wind's Point and the Wych*. The foliation, however, is often 

 more obvious in the hornblendic varieties of the gneiss, which, 

 although not so thinly bedded, often presents a finely ribboned 

 appearance. For the most part these fine-grained gneissic rocks are 

 rather deficient in quartz, which is frequently altogether absent. When 

 the felspar and quartz prevail, the beds are usually thicker, and the 

 rocks sometimes gneissoid or granitoid. The bedding is massive or 

 obliterated in the southern half of Midsummer Hill, the northern 

 extremity of Swinyards Hill, and north of the Wych. In the gneiss- 

 oid and granitoid rocks, including the granite, felspar is usually the 

 dominant mineral, but not always so, some rocks near St. Ann's 

 Well being rich in mica, with little or no quartz, and without ajiy 

 obvious gneissic structure. The granitoid varieties are, for the most 

 part, coarse-grained, and weather very rugged on the siu'face, as is 

 the case about the Worcestershire Beacon. Between the extremes, 

 there are many vaiieties, dependent on the relative proportion of its 

 constituent minerals and on their state of crystallization. 



The granite never appears moulded upon the other rocks, as is the 

 -case with erupted rocks, as for instance the traps. It does not, like 



I prefer, however, restricting the name syenite to granitoid rock having horn- 

 blende in lieu of mica. 



* Professor PhiUips admits the probable metamorphic origin of some of these 

 gneissic rocks {op. cit. p. 50) ; but he appears unwilling to allow to the more mass- 

 ive granitoid and hornblendic rocks a similar derivation, and regards the banded 

 and ribboned structure which he notices "as accompanying most of the syenitic 

 rocks of the Malvern Hills as indications of crystalhzation under restraint" 

 (p. 46), although elsewhere he observes that we may perhaps admit for some of 

 these bedded hornblendic and laminated felspathie rocks a similar origin and 

 more considerable metamorphosis corresponding to the easier fusibility of the 

 hornblendic element (p. 48). See further, p]5. 46 and 49. 



