^^^' 55'] STRUCTUEE OF THE SOUTHERN MALVERJiTS. 133 



readily traced south-south-eastward from the summit of the hill, 

 and may be seen on the roadside near the bottom of the ' Yalley 

 of White-leaved Oak ' (across which these rocks appear to pass) to 

 terminate against the gneissic and schistose series of Chase End Hill. 

 The Archaean rocks are, accordingly, not completely cut out in 

 the manner supposed b}^ Phillips,^ but are reduced to a narrow 

 isthmus. 



At the top of the hill the strike of the series is generally from 

 north-east to south-west, but elsewhere it shows a clear relation to 

 the boundaries of the strip, the prevailing dip being easterly, as on 

 the eastern side of the hill (see map, PL XIII). 



The western slope and the north-western corner of Haggedstone 

 Hill are formed almost exclusively by the Hollybush Sandstone, 

 together with an associated series of igneous rocks. The junction 

 of the sandstone with the gneissic series can be determined with 

 fair accuracy for a considerable part of its course. On the northern 

 slope of the hill it is difficult to follow, since, unlike the majority of 

 important junctions in the district, it is indicated by no depression, 

 or marked change in the angle of slope of the surface ; but south of 

 the summit its position may be determined within narrow limits, 

 although it is actually visible only in the large quarry near White- 

 leaved Oak. The relations of the two series on Raggedstone Hill 

 have been regarded by Holl ^ and Symonds ^ as proving uncon- 

 formable superposition of the sandstone upon the older series ; but 

 careful examination indicates that the junction is a fault, both in 

 the northern and southern portions of the hill. 



The Hollybush Sandstone in the former locality appears to dip, 

 on the whole, uniformly west-north-westward, at an angle varying 

 from 40° to 43° ; the outcrops (see fig. 2, p. 134), plotted out ac- 

 cording to the character of the slope, indicate that the beds abut 

 against the gneissic series ; while the long dyke is abruptly cut off 

 towards the south-east in a way which is best explained by a fault. 



Here the sandstone shows a broken anticline, the summit of 

 which forms a small sharp ridge running parallel to the junction. 

 The axis of the anticline rises south-south-eastward. This fold 

 was seen and figured by Murchison,"* though he gave it a cone of 

 crystalline rock, for the existence of which, however, I have seen 

 no evidence. At the southern end of the quarry the fault is nearly 

 vertical (see fig. 4, p. 136). 



On the east, a series of glossy sericite-schists dip on the whole 

 east-north-eastward ; near the junction they are thrown into a series 

 of small folds, pushed over towards the south-west, and with axes 

 rising towards the south or south-south-east. The sandstone is 

 separated from the schists by a few feet of brown, greyish- white, 

 or green sandy limestone, dipping, like the adjacent sandstone, at a 



1 Mem. Geol. Surv. vol. ii (1848) pt. i, p. 25. 



- Quart. Journ. Geol. Soc. vol. xxi (1865) pp. 89, 92, 97 et seqq. 



3 ' Kecords of the Rocks,' 1872, p. 34. 



* ' Silurian System,' 1839, p. 418. 



