LINGULA FLAG AND TREMADOC SLATE SERIES. 65 



including some bands of trap, composed of felspar and hornblende. 

 The eruptive rock is an ancient lava, consolidated for the most 

 part underground, or under the sea. The great deposit of shale 

 must have been formed in calmer and probably deeper water than 

 the Hollybush Sandstone, there having been, doubtless, a continual 

 subsidence of the sea-bed, interrupted by occasional volcanic out- 

 bursts.^ 



The Black Shale has yielded, among the Trilobites, species of 

 Conocoryphe, Olenus, SphcEfophthahntis, Agnostus ; and among the 

 Brachiopods, Lingiila and Kuiorgina {Obolella) cingulata. 



The upper portions of the INIalvern Shales are of a lighter 

 colour, and were called the Dictyonema Shales by Dr. Holl, on 

 account of their being characterized by the presence of D. sociaJis. 

 He states that this Hydrozoan occurs in North Wales immediately 

 above the Lingula Flags. The beds are grouped with the Dolgelly 

 and Lower Tremadoc rocks. (See Fig. 14.) 



SHROPSHIRE. 



Shineton Shales, etc. — In Shropshire the dark blue micaceous 

 shales which extend from near Evenwood by Cressage and 

 Shineton, on the Severn, to within a mile of Wellington, and 

 which underlie the Hoar Edge Grits (Caradoc), are grouped by 

 Dr. C. Callaway with the upper part of the Malvern Shales and the 

 Lower Tremadoc Beds. They contain Linguklla Nichohoni, 

 Asaphelliis Homfrayi, and species of Asaphus, Olenus, Agnostus, 

 etc., which, however, are mostly new species, according to Dr. 

 Callaway. He terms these beds the Shineton Shales. (See 

 Fig. 6, p. 44.) 



About 25 miles south-west of Shineton, there is a small exposure 

 of shales at Pedwardine, near Brampton Bryan, containing Dictyo- 

 nema socialis and Lingulelln Nichohoni, which Dr. Callaway would 

 correlate with the Malvern Dictyonema-%\i'a\.Q,'s>? Furthermore, 

 forming a continuous band between the Shineton Shales and the 

 quartzite which rests upon the Wrekin, is a series of thin-bedded, 

 micaceous, green sandstones, which Dr. Callaway identifies with 

 the Hollybush Sandstone. The Brachiopod Kutorgina cingulata 

 (:= Obolella, Phillipsii) occurs plentifully in a quarry near Neves 

 Castle. The sandstone is also found at Lilleshall, five miles north- 

 east of the Wrekin. 



MIDLAND COUNTIES. 



At the Lower Lickey ridge there are quartzites — used for road- 

 metal — which, according to Prof. C. Lapworth, are covered 

 unconformably by the Llandovery Beds.^ (See Fig. 33.) Mr. 



^ See J. Phillips, Mem. Geol. Survey, vol. ii. part i, pp. 51, 54. 

 2 Q. J. xxxiii. 655 ; G. Mag 1S78, p. 333. 

 G. Mag. 1882, p. 563; see also VV. J. Harrison, Midland Naturalist, viii. 70; 

 and H. H. Howell, Geol. Warwickshire Coal-field. 



