Yol. 56.] SHALES OF THE WELSH BORDERLAND. 



389 



Identical beds are also exposed behind Coppice House, and in 

 the road between the railway-station and Southbank they exhibit 

 exactly the same lithological characters : namely, a series of alter- 

 nating calcareous shales and nags underlain by hard flagstones. 

 The dip is the same in amount, but the direction has slightly 

 changed to S. 20° E. The beds here yielded Cyrtograptus' Linnarssoni, 

 Cyrtograptus sp., Monograptus Flemingii var. a, M. Jcelceli, Perner, 

 M. priodon, M. vomerinus, M. dubius, and Orthoceras subundulatum. 

 These beds undoubtedly represent the C.-Linnarssoni zone. 



Zone of Cyrtograptus rigidus, Tullb. — Following the left 

 bank of the stream, no exposures occur for some little distance, 

 but beds are again seen where a footbridge crosses the brook ; these 

 are much softer than those previously noticed, and in consequence 

 weather far more deeply. A_t the footbridge I collected the grapto- 

 lites enumerated in Table III, col. B (p. 390). Although Cyrto- 

 graptus rigidus has not been found, the presence' of Monograptus 

 retroflexus and the general assemblage of forms clearly indicate the 

 C.-rigidus zone. The beds here strike parallel to the stream, and 

 dip in the same direction as before. 



A little lower down the brook, similar beds are seen on the right 

 bank. This exposure is good, but the rocks are so deeply weathered 

 that it is hard to obtain more than mere fragments of fossils. I have 

 been able, nevertheless, to identify the forms enumerated in Tablelll, 

 col. C (p. 390). The presence of M. retroflexus again indicates that 

 this exposure is in the C.-rigidus zone. There is a break in the suc- 

 cession below this point, and the next beds are seen just above where 

 the stream bends in such wise as to run parallel with the railway. 

 These evidently represent the base of the C.-Lundgreni zone. 



Zone of Cyrtograptus Lundgreni, Tullb. — The beds seen 

 in the above-mentioned exposure consist of calcareous shales with 

 Monograptus Flemingii vars. I & fl. The list of fossils obtained 

 is given in Table III, col. D (p. 390). 



Passing under the railway, the strata of this zone are excellently 

 exposed. The beds run very nearly parallel to the direction of the 

 stream, but those near the railway-station are slightly higher, and 

 the dip continues steep. I collected fossils at various points along 

 this exposure, and these are enumerated in Table III, cols. E & F. 



Slightly lower down the stream, on the right bank, M . dubius and 

 M. Flemingii var. h were found (see Table III, col. G). Still 

 lower down on the right bank, the fossils found included those 

 enumerated in Table III, cols. H & I. The rocks from which these 

 fossils are obtained are the typical, bluish-grey, calcareous shales 

 with harder bands. 



There is again a break in the succession after a footbridge, and 

 the next beds are seen a little lower down on the left bank. The 

 rocks here consist of earthy calcareous flagstones, dipping S. 20° E. 

 at 45°, and yield M. Flemingii var. h and M. dubius (Table III, 

 col. K, p. 390). 



