ARCH^AN. 45 



and Cardington. Quartz-schists are exposed at Rushton. Prof. 

 Bonney remarks, that in the Wrekin we have a portion of an 

 ancient volcanic hill which has ejected rhyolitic lavas and scoria. 

 At Lilleshall Hill rhyolitic agglomerates and other volcanic rocks 

 are met with. 



Lichy Hills, Worcestershire. — In this range the principal rock is a 

 quartzite, bearing considerable resemblance to that which flanks 

 the Wrekin. Formerly this rock was regarded as altered Llandovery 

 sandstone, but the investigations of Mr. F. T. S. Houghton and 

 Prof. Lapworth have shown that, while there is a quartz-grit of 

 Llandovery age, the quartzite proper is an older rock. Prof. 

 Lapworth has also discovered that at the south-western end of the 

 range there are felspathic ashy beds, and a felstone, with a general 

 resemblance to the rocks in the Wrekin area.^ 



Hartshill Ridge, Warivickshire. — A ridge of quartzite north-west 

 of Nuneaton (formerly regarded as Millstone Grit) has been shown 

 by Prof. Lapworth to be overlaid by fossiliferous Cambrian rocks. 

 It is underlaid by Archaean rocks, consisting of felspathic mud- 

 stones and ashes, with intrusive quartz-felsite.^ (See p. 66.) 



Charnwood Forest, Leicestershire. — The oldest rocks of Charnwood 

 Forest, in the opinion of Dr. H. B. Holl, and others, may be 

 Pre-Cambrian. Apart from the granitic rocks (see sequel), there 

 is a series of slates, grits, breccias, and agglomerates, among which 

 are some porphyroids, probably lavas. Grits occur at Forest-Rock 

 Inn and Bawdon Castle ; volcanic breccia at W'hitwick and Mark- 

 field ; and agglomerate at High Towers. 



The Rev. E. Hill and Prof. T. G. Bonney, who have more 

 recently investigated the district in detail, observe that the Charn- 

 wood Forest rocks seem to fall naturally into three great groups, 

 which, however, are not separated by any very sharp lines of de- 

 marcation : ^ — 



Slates of Swithland and Groby (visible only in the more southern part of 

 the Forest). 



Sharpley and Peldar Tor rocks (tuffs, porphyroids, etc.), with the 

 agglomerates of Cadman (and their equivalents in Bardon Hill), 

 which are probably succeeded by the finer beds of the quarry near 

 Whitwick School House. 



Some portion of this upper division may be represented by the 

 Forest Gate Beds in the north-east ; and the upper limit of the group 

 further south seems to be marked by the pebble-beds and quartz 

 grits of the (Woodhouse) Hanging Rocks, the Brande, the Stable 

 Quarry (Bradgate), and Steward's-Hay Spring. 



Slate-agglomerate. 



Coarse ash-beds of the Monastery, the Hanging Stones, Timberwood 

 Hill, Bensclifif, etc. 



/Blackbrook series, ashy beds, flinty slates, banded grits, etc. (Whittle Hill 

 \ honestone, etc.) 



^ T. G. Bonney, on the Archrean Rocks of Great Britain, Brit. Assoc. 18S5. 



^ Proc. Birmingham Phil. Soc. iii. 206. 



" Q. J. xxxiv. 199 ; xxxvi. 349. See also James Plant, G. Mag. 1865, p. 233. 



