120 



CARBONIFEROUS LIMESTONE, OR GLEE HILL MARBLE. 



a triple complication, consisting of a central conical mass between two other fractured 

 strata, the angle of dip being different in each. (See diagram, PI. 30. fig. 5.) This 

 face of rock, which has been recently laid bare, shows powerful and forcible disloca- 

 tion, the edges of the beds on the sides of the central wedge-shaped mass being much 

 shattered. The strike is here south-south-west, north-north-east, and the dip 25° west- 

 north-west. Other dislocations at the Stable and Navers quarries, are accompanied by- 

 many contortions. At the point of flexure between the Navers and Gorstley Rough, the 

 fallen masses frequently overspread the limestone with heaps of party-coloured shale, the 

 subsidences of the upper cliff in a single night, interrupting the labour of months 1 . 



Carboniferous Limestone of Oreton. — The limestone of Oreton situated at the northern 

 extremity of the Glee Hills, has the same relations to the overlying and underlying 

 strata as the limestone at the southern end of the carboniferous tract, and constitutes 

 a similar, narrow, broken zone, thinning out at each end. In the central portion the 

 strata repose upon the Old Red Sandstone at an angle of about 30°, dipping to the south 

 or to a few points east and west of south. This limestone, however, rises into a low 

 ridge by itself, and is not overlaid by a cap of millstone grit like that above described. 

 (See PI. 30. fig. 1.) Owing to this favourable position and its superior quality, parti- 

 cularly in the central parts of the little ridge, this stone is very advantageously worked. 

 The beds extracted vary in united thickness from forty to fifty feet, and present the 

 following details in descending order. 



Impure shelly limestone and shale. 



Top white rock "I 



T , , , , , , . All these beds of limestone are of good quality, 



Jumbles (a grey-coloured rock) v 43 u 



„ „ , ° f the "bottom whites" the best, 



.bottom whites J 



Blue shelly limestone. 2 



At the western termination the limestone is associated with much shale in the following maimer : 



Broken limestone -i 



Thinly laminated dark shale.... J ' "' 



Blue limestone .„ 



Shale with irregular courses of sandy limestone 



Brownish yellow shelly limestone of compact structure. 

 Solid white limestone slightly oolitic. 



Dip 1 5° to the south-east. 



The above sectional lists prove that the quality of the limestone, as before stated, de- 

 teriorates rapidly toward the western extremity of the zone, and the same maybe said of 

 its eastern termination; for near Farlow Factory and on the left bank of the Rea Brook, 

 a hard and impure variety associated with shale, passes down into a conglomerate, forming 



1 In the Map of the Ordnance Survey which I coloured in the field, and a copy of which is deposited in the 

 Geological Society of London, all these dislocations can be clearly seen. 



2 These quarries have afforded aU the finest specimens of the grey oolitic limestone known as the " Clee Hill 

 marble." Columns of great length and breadth have been occasionally extracted. Beautiful examples of these 

 may be seen in the mansions of Oakley Park, Downton Hall, and Hoptoun House. 



These beds of limestone are 

 very inferior in quality. 



