Notices of Memoirs — Cope ^ Lamas — The Berinjns. 33 



than usual, whereas the reverse is the case in iv (M'Coy's type- 

 specimen of' G.' fasciculntiis). The former does not appear to be 

 distorted, and is therefore a more evolute form than the rest, but in 

 the absence of other similar specimens it is provisionally at least 

 included in M'Coy's species. M'Coy's specimen is distorted, and the 

 irregularity noted may be due to this distortion, for, juflging from 

 Dr. Foord's figure of the fossil (pi. xxxvii, fig. 5a), the anterior 

 extremity of the outer whorl appears to be abnormally high. It may 

 be mentioned that the examples of the species figured by Dr. Foord 

 differ considerably in their relative dimensions. 



The English localities, then, of Pericyclus fasciculatiis, so far as 

 known to the present writei", are confined to the western part of 

 Derbyshire and the adjoining part of Staffordshire. They are : — (i) 

 near Matlock, Derbyshire ; (ii) Kniveton, 2 miles north-east of 

 Ashbourne, Derbyshire ; (iii) Bradbourne, about 2 miles north of 

 Kniveton and about 10 miles south-west of Matlock, Derbyshire ; 

 and (iv) Beeston Tor, in North Staffordshire, about 1 mile east of 

 Grindon and about 7 miles west of Bradbourne. 



o^OTiOES OIF nynE3VLOiE,s, etc. 

 On the Igneous Kocks of the Berwtns. By T. H. Cope and 



J. LOMAS.^ 



OWING to cross folding a dome-like structure has been impressed 

 on the Berwyns. From the axis which lies about Llanrhaiadr- 

 yn-Mochnant and Craig-y-Glyn the beds dip outwards on every side. 

 The arch of the dome has been denuded, so that we get shales and 

 limestones of Llandeilo age occupying the central area, while slates, 

 grits, and limestone of Bala age form an almost continuous ring of 

 hills on the margins. 



Igneous rocks are associated with the sedimentaries. Three bands 

 in the peripheral series can be traced continuously for a distance of 

 thirty miles from the Mountain Limestone beds which overlap the 

 series on the east, through the hills above Corwen and Bala to the 

 Vyrnwy watershed. A fourth band also occurs in this series about 

 Llanarmon. 



In the central area other igneous rocks are exposed, generally of 

 a more acid type. 



The igneous series have been regarded as contemporaneous 

 volcanic ashes, and recorded as such in the Survey maps. We have 

 failed to find any instance of undoubted contemporaneous action, and 

 regard all the igneous as intrusive. In places they are seen to cut 

 across the sedimentaries at right angles to the strike. 



In this paper we only deal with a small part of the peripheral 

 series as displayed about Llansantffraid-Glyn-Ceiriog where the river 

 Ceiriog in cutting a deep gorge across the strike of the beds has 

 exposed magnificent sections. 



^ Abstract of a paper read before the British Association, Soutbport, Sectiou C 

 Geology), September, 1903. 



DECADE V. — VOL. I. — NO. I. 3 



