Geology of the South-east of Devonshire. 



463 



of clay-slates, of an uniform character and composition, we see them pass from 

 clay-slate, through talcose and micaceous slate, to true gneiss — the progressive me- 

 tamorphic forms of strata, which are the geological equivalents of the lower part 

 of the old red sandstone. 



§ 1 . The coral limestones of Newton Bushell, Ogivell, Kingsherswell, Barton, and 

 Torquay. — These deposits form so striking a feature in the scenery of this portion 

 of the county, and the map, PI. XLL, so sufficiently indicates their positions, 

 that a detailed account of their range and extent is not required. 



The thin calcareous deposits constitute the uppermost portion of the older rocks 

 of South Devon, and in most places they are distinctly stratified ; they also present 

 two systems of divisional joints, one set of which runs a few degrees W. of N., and 

 a cross set S. of E. ; locally, however, considerable deviations will be observed, 

 some of which are given in the following table : — 



Localities. 



Range of joints. 



Strike of the 

 beds. 



Dip of the 

 beds. 





Chercombe Bridge 



Do. Second Quarry 



Ogwell Park 



N. 45° W. 

 N. 45° W. 



id. 

 N. 70° W. 

 N. 45° W. 

 N. 25° W. 

 N. 45° W. 

 N. 25° W. 

 N. 45° W. 



N. 



N. 

 N. 45° W. 



N. 25° E. 

 N. 45° E. 



id. 



id. 



N. 65° E. 

 N. 45° E. 



N. 



E. 



N. 70° W. 

 N. 45°E. 



N. 25° E. 

 id. 

 id. 

 id. 



N. 



N. 25° E. 

 N. 45° E. 



40° E.S.E. 

 id. 



60° E.S.E. 

 S.E. 



In three places. 

 The same on the 



other side of the 



stream. 



Orchard-well 



Wolfsgrove 



Ipplepen 





Another curious point connected with the structure of many of the great lime- 

 stone masses of South Devon, particularly those of Brixham, will be noticed under 

 the head of cleavage. 



The relations of these large calcareous masses to the subjacent slate rocks is not 

 very evident. At Pulser, the shales, at their junction with the base of the Torbrian 

 limestone, through a thickness of about two feet, contain small lenticular portions 

 of limestone, arranged in parallel lines, which correspond with the bedding. About 

 Ogwell (fig. 3.) the limestone sets on, in compact beds, after a few trifling alter- 

 nations with shales, and such is very generally the case. 



Although these limestones dip in the same direction with the slate rocks of the 

 district, and often at considerable angles, they do not appear to descend with them 

 to any great depths, but either to thin away, as at Staverton (as does also the lower 

 Ashburton band at Staple Hill), or else to end abruptly downwards, as near Newton 

 (road-section) fig. 7. PL XLII. and the limestone of Denbury, as if they had been 

 formed on a previously deposited mass of sediment, now converted into shales 

 and slates. At Bunker's Hill, near Totness, the limestone, which on the south 

 side of the hill dips with the slates composing the central portion, wraps round, 



3 o2 



