536 



iMU'OUT— 1884. 



sandstone, but the investigations of !Mr. F. T. llouglitoti, Professor Lap- 

 worth, and others, have shown that, while there is a quartz-grit of Llan- 

 dovery age, the quiiTtzito proper is an older rock.' Professor Lapworth 

 has'also discovered that at tlie south-western end of the range there are 

 felspathic ashy beds, and a felstone, with a general resemblance to that 

 abounding in the Wrekin area. 



(0.) The nartxJu'll Itiilgc. — l*J.\ten(]itig for about two and a hnlf miles 

 in a north-westerly direction from the town of Nuneaton, is a ridge of 

 quartzite forming the eastern flank of the Carboniferous district of War- 

 wickshire, and bounded in that direeLii)u by a fault, on the other side 

 of which are the Keuper bods. This (juart/.ite has been mapped and 

 described by the Geological Survey as altered ]\Iillstono Grit. Professor 

 Lapworth, however, has recently di.scoveicd that it is overlain by a series 

 of Upper Cambrian beds, coutaiiiii.'g charueteristic fossils, which are suc- 

 ceeded by the Coal-measures of the district, and is underlain by felspathic 

 mudstones and aslu'S, among which occurs intrusively a ((nartz-felsite.-' 

 Cei'tain diorites intrusive in both (juartzitc and tlie I^pper Cand)rian beds 

 have been described by Mr. S. All port."* 



(7.) The (Jharmvood Fared UnjiiDi. — This interesting district lies to 

 the north-west of t..e town of Leicester, and consists of a group f)f hills 

 cropping out from beiunith Triassie beds, which have occupied its ancient 

 valleys, and possibly once buried many of its summits. It is, in short, a 

 pre-Trifissic highland region which has been again laid bare by denuda- 

 tion. The area occupied by the older rocks measures, roughly, nearly nine 

 miles from NW. to SE., aiul rather more than four from SW. to NE., but 

 it is somewhat interrupted by overlying Trias. At the north-west end, in 

 close proximity to the older rocks, a patch of dolomitized Carboniferous 

 limestone is exposed, and along the north-west flank is the Leicestershire 

 Coalfield. Tlie district has been investigated bv the Ilev. E. Hill and 

 myself,^ and the following is a brief resume oi our conclusions. Omittnin' 

 for the present sundry masses of igneous rock, generally rather coarsely 

 cry>talliue, the Charnwood Forest series forms probably the more 

 southern portion of an elongated anticlinal dome. The axis of this 

 points from rather N". of NW. to S. of SE. The mass is severed by an 

 anticlinal fault, and, as I think, by a larger parallel one to the west. The 

 beds on the opposite side of these are rather dissimilar, but we think 

 that sundry horizons may be identitied with tolerable certainty, and the 

 following general succession established. The lowest group, exposed 

 only at the northeru extremity of the Forest, consists of slates and gritty 

 beds. The latter have bfcn called quartzites, but they are not at all normal 

 representatives of this group, and they appear for the most part to be 

 fine volcanic detritus of an acid character. To this succeeds a great series 

 of grits, slates, volcanic ash, and agglomerates, some of the last-named 

 being very coarse and containing at certain horizons rounded masses 

 of a rliyolitic rock, at others large fragments of a greenish slaty roclc. 

 Then comes, on the western side, at High Sharpley, a schistose porpliy- 

 ritic rock, overlain apparently by a less schistose variety called the 

 Peldar Tor rock, over -which come more agglomerates. Yet higher, 



' JProc. liirmingham P/iil. S<>c., vol. iii. \). 20C. 



■ For informjition on these two rcfrions, and for the opportunity of examining 

 some of I ho more important sections, I am indebted to Professor Lapworth. 

 » Q. J. G. iS'., vol. XXXV. p. G:{7. 

 * Q, J. (1. (S'., vol. xxxiii. p. 751 : xxxiv. p, UK* ; x.Kxvi. p. ;'.:i7. 



