556 MR. H. D. ACLAND ON A VOLCANIC SEEIES [Aug. 1 8 98, 



34. On a YoLCANic Seeies in the Malveen Hills, near the 

 Heeefoedshiee Beacon. By H. D. Acland, Esq., E.G.S. 

 (B,ead May 18tli, 1898.) 



The rocks of the Malvern Hills have afforded scope for much study 

 and discussion. Dr. Holl, Mr. Rutley, and Dr. Callaway have 

 elaborated papers on them. Mr. Rutley's relates mainly to the 

 general character of the rocks ; while Dr. Callaway devotes himself 

 to an enquiry into the genesis of the crystalline schists, and the 

 production of secondary minerals in shear-zones. 



I propose to deal with a small area of the hills and describe 

 some of the rocks to be found there. The district lies east and 

 south-east of the Herefordshire Beacon, which has three spurs. 

 The northernmost is Tinker's Hill, south of that comes Broad Down, 

 and south of that again Hangman's Hill. The latter is, in its turn, 

 bounded on the south by the ' Silurian Pass,' so named in the 

 Geological Survey memoir by the late Prof. Phillips.^ The Beacon 

 Hill itself is of the same character as the main axis of the hills. 



Prof. Phillips called attention to these rocks, and remarked that 

 they ' appear partly in lines like dykes.' Dr. Holl also mentioned 

 them, and considered them to be sandstone altered by the 

 intrusion of trap-dykes. He noticed that some of the dykes contain a 

 large proportion of augite.^ In a note to p. 100 (op. cit.) Dr. Holl 

 says that fragments of these rocks are found in the Gullet Wood 

 conglomerate. This statement requires investigation, as it might 

 form a clue to the age of the series. 



Dr. Callaway has expressed the opinion that these rocks constitute 

 a second pre-Cambrian group, and that they are of Pebidian age.^ 

 Mr. E,utley devoted a considerable space to them. He subjected 

 them to careful microscopical analysis, and came to the conclu- 

 sion that some are anorthite-basalt and others devitrified* obsidian.* 



Prof. A. H. Green described more minutely than previous 

 writers the various rocks in this area." It is scarcely with the 

 hope that I may be able to add anything to his observations that I 

 offer the following remarks ; but, living as I do in the neighbourhood 

 of this interesting series of rocks, having paid many visits extending 

 over several years to them, and having commenced these notes some 

 considerable time before the publication of his paper, I venture with 

 all diffidence to place on record some of the results of my work. 



The rocks of this area are tuffs, felsites, andesites, and basalts or 

 dolerites. 



The felsites are very persistent in their character : they have 



1 Greol. Surv. Mem. vol. ii (1848) pt. i, p. 29. 



2 Quart. Journ. Geol. Soc. vol. xxi (1865) pp. 93 & 100. 



3 Ih2d. Tol. xxxvi (1880) pp. 536 & 537. 

 * Ibid. Tol. xliii (1887) pp. 497-499. 



' Ibid. vol. H (1895) pp. 1-8. 



