﻿558 MR. T. F. SIBLY ON THE CARBONIFEROUS [Aug. I905, 



(South Wales) ; and I have recently recorded it at the base of S x afc 

 Cheddar. 



Athyris cf. expansa (Phill.) ' Geology of Yorkshire' vol. ii (1836) 

 p. 220 & pi. x, ng. 18, occurs persistently throughout C 2 and S^ 



' Athyris ' ct*. glabristria (compare Phill. op. cit. p. 220 & pi. x, 

 fig. 19), Spirifercl.furcatuSj'M.'Coy, 'Syn.Carb. Limest. Eoss. Ireland' 

 (1844) p. 131 & pi. xxii, fig. 12, and Camarophoria isorhynclia 

 (M'Coy) op. cit. p. 154 & pi. xviii, fig. 8, occur abundantly at the 

 base of S r Productus punctatus. Martin, and ' Clisiophyllum ' 

 (Carcinophyllum) sp. are very common at the same level. 



Oyrtina carbonaria (M'Coy) < Brit. Pal. Foss.' (1855) p. 442 & 

 pi. iii d, figs. 12-18, is abundant near the base of S,. 



Derby a sp. has been obtained from C 2 . I have recently found 

 the same form in C 2 in the Mendips. 



III. The Woodspring Ridge (Mibble Hope). 



This ridge of Carboniferous Limestone, 2 miles in length, lies 

 2 miles north of, and runs almost parallel to, the Weston- Worle 

 ridge. The average dip of the beds is about 30° southwards, and 

 the general strike is W., a few degrees S. 



The sequence represented here extends from the upper part of 

 the resup inata -subzone [Z J to the ' Caninia-Oolite ' in the Syringo- 

 thyris-Zone. Special interest attaches to this development, owing 

 to the occurrence of contemporaneous igneous rocks 1 at Horizon y. 



The complete sequence is displayed on the coast at the eastern 

 end of the ridge, where it consists of a very fossiliferous develop- 

 ment of Z 2 and y, with volcanic ash at the top ; succeeded by an 

 excellent development of the ' let minosa- dolomites' and the ' Caninia- 

 Oolite.' The combined thickness of the ' Zammosa-dolomites ' and 

 Canima-Qolite ' lies between 200 and 250 feet. The upper part 

 of Z , including Horizon y, is finely displayed all along the coast- 

 line on the north side of the ridge. Three other exposures of the 

 igneous rocks occur, the repetition of these exposures being due to 

 two small dip-faults, running almost at right-angles to the coast- 

 line. On the south side of the ridge, at the western end, the top of 

 the ' laminosa-dolomites ' and the fossiliferous sub-Oolite beds are 

 well exposed. 



The Faunal Sequence. 

 Zaphrentis-Zone (including the upper part of Z 2 and Horizon y). 



Coral-fauna : — 



Zapkrentis aff. Phil lip si. Amplexus cf. coralloides. 



Zaphrentis aff. cornucopia. Syringopora 9. 



Caninia cylindrica. Michelinia favosa. 



1 For a detailed description of the igneous rocks, see Sir A. Geikie & 

 A. Strahan, 'Summary of Progress of the Geological Survey for 1898' 

 pp. 104-11 ; and C. Lloyd-Morgan & S. H. Reynolds, ' The Igneous Rocks 

 associated with the Carboniferous Limestone of the Bristol District' Quart. 

 Journ. Geol. Soc. vol. lx (19U4) p. 137. An excellent map of the Woodspring 

 Ridge accompanies the latter paper. 



