650 ME. W. GIBSON" AND DE. WHEELTON HIND ON THE LAug. 1^99, 



3. Succession of Limestone and Igneous Rocks. 



(a) Qnarry-section, Astbury Limeworks. — The quarry is 

 about 1 mile north-east of Mow Cop Station and is represented on the 

 Geological Survey map by a small patch of dark blue, ending off 

 to the west against the Eed Rock Fault, and lying between this 

 fault and another to the east, in the midst of beds mapped by the 

 officers of the Geological Survey as Yoredale Shales. 



The limestone was worked for a long time in an open quarrj' ; but 

 of late years these workings have been abandoned, and the limestone 

 is now obtained by an adit commencing on the west in Triassic 

 rocks. The limestone is massive and thickly bedded, containing 

 corals and encrinites and the fossils usually found in the Carboniferous 

 Limestone, among them CJionetes papilionacea. A detrital bed, con- 

 taining rolled shells, occurs in the upper portion. The massive lime- 

 stone is shown in the old quarry to be overlain by calcareous shales 

 with thin bands of impure limestone, a series of passage-beds which 

 is generally foand to succeed the Mountain Limestone massif in 

 North Staffordshire, Derbyshire, and South-west Yorkshire. 



Fig. 2.- 



N.W. 



-Section along CD (see map, fig. 1, p. 548) on the scale of 

 25 inches to the mile. 



a = Limestone. 



h = Shales and thin limestones. 



c — Agglomerate and tuif. 



d = Shales, limestones, and tuffs. 

 e = Shales with coal. 



At the present day the quarry is much overgrown by grass, 

 especially on the west side. The igneous rock, however, is well 

 exposed in the north-eastern corner in a face about 25 feet high and 

 1 60 feet long, while recent land-slipping has brought to light other 

 sections on the eastern and south-eastern sides. 



The mass in the cliff-section is an agglomerate — consisting of 

 angular fragments of green tuff — often vesicular, embedded in a 

 greenish calcareous matrix. Fragments of marmorized limestone are 

 not infrequent, and in some places there are corals and other fossils 

 roughly occupying certain layers in the mass. The rock does not 

 disintegrate rapidly, but weathers on the outside to an ochreous 

 colour. It is much harder in the cliff than in any of the other 

 exposures. The agglomerate is underlain by thin limestones and 

 calcareous shales ; the dip is into the hill, or eastward. The top of 

 the mass is not seen, being covered by grass and debris. 



South of the cliff occurs a gap of 150 feet in which no 

 rock is visible, while south-west of the gap thin limestones and 



