Daviesiella llangollensis in Berhysltire. 467 



be regarded as 83, probably about the middle of that sub-zone. 

 Pending a detailed study of the overlying Chee Tor Eock I am 

 prepared to accept this view. 



In Wye Dale, between the Daviesiella exposure and Pig Tor, 

 on the way to Buxton, lower beds are seen, but these have not yet 

 been examined in detail. On close study these may assist in arriving 

 at more definite conclusions. 



Where to place the upper limit of D. llangollensis also remains 

 for future investigation. It is probable that it may extend up to 

 the base of the massive white limestones of the Chee Tor series. 



The latter series is some 500 feet in thickness, and is surmounted 

 by a lava-flow — the Lower Lava of the Miller's Dale area — and this 

 is again overlain by about 150 feet of limestones, mostly thickly 

 bedded, and including some interesting types. One of the most 

 important of these is a mottled bed, observed many years ago by 

 Messrs. J. Barnes and W. F. Holroyd ^ in a small quarry near the 

 Glory Mine at Priestcliffe Ditch, not far from Miller's Dale. The rock 

 consists of a light-coloured and fine-grained " matrix ", with dark- 

 coloured irregularly shaped patches of a fine-grained limestone. 

 On microscopical examination the dark patches are seen to contain 

 an abundance of foraminifera, while the lighter " matrix " is 

 practically barren of such organisms. The rock agrees exactly with 

 the well-known " pseudobreccia ", which is so characteristic of D^ 

 in the typical Avon Section, ^ and at Gower, etc.^ A similar " pseudo- 

 breccia " also occurs in the higher portions of the Dj^ sub-zone in the 

 North- Western Province.'* 



Attention might also be called to the occurrence of calcite- 

 mudstone in Sandy Dale, near Miller's Dale, in the same series of 

 limestones lying between the Upper and Lower Lavas. This bed 

 was pointed out to me by Professor 0. T. Jones on the occasion of a 

 recent class excursion from the Manchester University. Some little 

 distance above the calcite-mudstone in the same dale, dark lime- 

 stones with chert-nodules are seen. These contain Lithostrotion 

 jiinceum in abundance, and are very little below the Upper Lava. 



In the massive white limestones, about 12 feet above the Lower 

 Lava, in Miller's Dale itself, Lithostrotion junceum, L. irregulare, 

 and L. martini occur, together with Cyrtina sejjtosa (quite typical) 

 and Chonetes aif. comoides. 



These limestones, which are part of the Miller's Dale Rock of the 

 Geological Survey,' are included by Dr. Sibly in D^, and this is in 

 agreement with the fauna. 



The Cyrtina scptosa from these beds is quite typical of Phillips' 



1 Barnes & Hohoyd, Trans. Manch. Geol Soc, vol. xxvi, 1900, pji. 561-8, 

 pis. 1-11. 



- See S. H. Reynolds, in Q.J.G.S., vol. Ixxvii, 1921, p. 234. 



3 See E. E. L. Dixon, in Q.J.G.S., vol. Ixvii, 1911, pp. 560 et seq. 



* See E. J. Garwood, in Q.J.G.S., vol. Ixviii, 1912, p. 477 ; also J. W. 

 Jackson, Geol. Mag., 1908, pp. 266-8. 



^ The Carboniferous Limestone, etc., of North Derbyshire, 2nd ed. (1887), p. 18. 



