74 



LIMESTONES. 



Upper western side of the summit ridge of May Hill. In this 

 — EY * feature the district resembles that of Ledbury, Woolhope 

 Wall-case 43. and Abberley. The composition of the limestone is very 



similar — locally rich in corals, irregularly aggregated into 

 very solid and compact rock, or separated into a multitude 

 of nodular beds, with intervening soft shales. The solid 

 masses of limestone are locally termed " Woolpacks." They 

 yield the finest and most abundant lime-flour, and seem to 

 prevail along the high and prominent crests of the hills. 

 The whole thickness of the Wenlock limestones, including 

 the intervening beds, is about 220 feet. In the great ma. 

 jority of cases, throughout the Silurian regions, it is the 

 lower part of the Wenlock limestone which is quarried for 

 lime-burning. This, in fact, is in almost every case the 

 most solid (and in mass the purest) part of the rock. It 

 generally requires at least one ton of coal for the calcination 

 of four tons of limestone. In this lower part of the rock 



corals are very abundant." (See " Memoirs 

 Survey," vol. ii., part 1., pp. 185, 186. 



) 



37. — Carboniferous limestone, grey, coralline lime 



stone. 



Well 



Salop. 



38. — Carboniferous limestone, compact, bituminous 

 limestone, containing fossil corals. — Brown's Hill Quarry, 

 County of Car lota, Ireland. 



39. — Bala limestone, very impure limestone, with nu- 

 merous casts of Orthis Actonice. — Haifa mile south of Pont 

 Rhiicaedog, Bala, Merionethshire. 



40. — Forest marble, shelly limestone, forming the upper 

 beds of the Great Oolite. — Bath, Somerset. 



This limestone usually shows much false bedding, and, like 

 the Stonesfield slate, is frequently used for roofing purposes, 

 and in slabs for flooring. 



41. — Forest marble, shelly limestone, formed chiefly 

 of Oyster shells. — Frome, Somerset. 



42. — Oyster bed, in Portland stone, shelly limestone, 



locally known by the name 

 of Purbeck, Dorset. 



Purbeck Po 



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