. Bulletin of the British Museum (Natural History), Geology. 12 W. F. WHITTARD. Fig. 6. Outcrops of Stiperstones (Quartzite) Member. View looking north from point south of Manstone Rock, between Devil's Chair and Cranberry Rock. so well seen as between Cranberry Rock and the Paddocks, and The Rock and Nipstone Rock, which significantly are the two lengths where the outcrop shows the most complex fault-pattern. Reliable figures for the thickness of the Stiperstones Member are difficult to determine. The angles of dip vary quickly and range from 40° to vertical, whilst in some places, as on both
. Bulletin of the British Museum (Natural History), Geology. 12 W. F. WHITTARD. Fig. 6. Outcrops of Stiperstones (Quartzite) Member. View looking north from point south of Manstone Rock, between Devil's Chair and Cranberry Rock. so well seen as between Cranberry Rock and the Paddocks, and The Rock and Nipstone Rock, which significantly are the two lengths where the outcrop shows the most complex fault-pattern. Reliable figures for the thickness of the Stiperstones Member are difficult to determine. The angles of dip vary quickly and range from 40° to vertical, whilst in some places, as on both sides of the River West Onny and at Nill's Hill, the dip is reversed to the east. Nowhere is there a section through the Member, neither the upper nor the lower limit is visible in more than a few places, and only indirect evidence of the thickness can be utilized. Topography is a most uncertain guide because the escarpment is continually being degraded, crags are actively being reduced in height and enveloped in scree-clitter and, by virtue of bedding and of jointing parallel to the strike, rocks fall on both dip and scarp slopes. The marked change of slope on the scarp side suggests the outcrop of the softer Shineton (=Habberley) Shales, Tremadoc Series, but this can be deceptive because at several locations undoubted exposures of quartzite occur in what, on this assumption, should have been Tremadoc ground. Consequently the Stiperstones Member may at times be below the surface but farther down the scarp than is expected, and its failure to crop out is due to 'scaling-off of the quartzites along the joints. On the dip slope, exposures are hardly ever seen owing to the blanket of quartzite blocks, heather and whinberry. How far west the top of the Member extends is frequently difficult to determine, and topography reveals little because the quartzites show a zone of gradation into the slightly less resistant Mytton Member. Thus the thickness of the Stiperstones Member as sho
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