242 Messrs. Buckland's and Conybeare's Observations on the 



line perpendicular to the drift of the strata^ amounts to 2 miles^ and from the 

 mean angle of dip, which exceeds 30°, we should obtain by calculation at least 

 one mile for the entire thickness of the strata, if continuous. But this being 

 considerably more than double of the known thickness of the mountain lime- 

 stone in any otherpart of the district, the repetition of the series in consequence 

 of a fault or faults is rendered highly probable. On the left bank of the Avon 

 the fault may be traced up the gulley, which bounds the northernmost of the 

 two Roman camps in Leigh Wood, ranging between Nightingale valley and 

 the arch leading to Mr. Miles's park. The nature of the ground prevents our 

 following it ; but since it is nearly in the same line with the fault of the Clapton 

 coal-field, it is not improbable that the two may be connected. 



To return to the right bank. The millstone-grit crowns the scarry brow 

 immediately below the northern rampart of the Roman camp, placed at the 

 summit of St. Vincent's rocks, and extends thence to the turnpike. Below the 

 turnpike the upper limestone presents a scar, at the foot of which a broad 

 slope, following the direction of the strata, affords an ea.sy descent to the river. 

 A sort of double terrace succeeds, presenting a slight escarpment, in which a 

 thin calcarous seam, the lowest probably of those of the upper hmestone, is 

 interposed between two of grit. The new road constructed in the face of the 

 bank has afforded a complete section of the other strata of the Hotwell series, 

 commencing with the lowest beds of the upper limestone. It begins near the 

 foot of the bank in contorted strata of limestone interposed between con- 

 torted strata of grit, abutting against the fault. In pursuing the road the fol- 

 lowing are the strata which have been observed and accurately measured by 

 Mr. De La Beche : they may be compared with the first 46 strata of Mr. C.'s 

 section referred by us to the upper limestone, the middle grit, the middle lime- 

 stone, and the lower grit of the upper limestone-shale. 



1. Contorted bed of Limestone between 







1 



contorted beds of Grit 





> Upper Limestone. 



2. Beds of Marl of uncertain thickness 



Ft. 



In.^ 





3. Rubbly Grit . . 



3 



6 





4. Green and red Marl 



9 









5. Loose Grit 



4 









6. Blueish, green, and red Marl 



13 



6 





7. Grit 



4 



6 



> Middle Grit. 



8. Grit 



4 









9. Rubbly Grit 



4 









10. Red Marl .... 



4 









11. Rubbly Grit 



. 3 



Oj 





