South-western Coal District of England. 241 



It includes the lower part of No. 1^ and Nos. 2 and S, of Thickness about 

 Dr. B., and from No. 9 to No. 31 of Mr. C. 60 feet. 



4. Lower grit, consisting of shale and grit alternating, and 

 having 2 thin coal-seams. 

 It includes Nos. 4, 5 and 6 of Dr. B., and from No. 32 to 

 46 of Mr. C. It appears behind the centre of the 

 colonnade near the Hotwell-house, whence it ranges 

 up the hill past the north end of Prince's Buildings, 

 and the new Hotwell-house towards the south-side of 

 the Mall. 

 The great deposit of mountain limestone is exhibited in the three succces- 

 sive cliffs of St. Vincent's rocks, the great quarry, and the black rock. The 

 first limestone beds of this series (from No. 47 to No. 60 of Mr. C.) do not ap- 

 pear in the cliff" of St. Vincent's rocks, but ascend a steep and grassy slope, in 

 which Nos. 52 and 54 present conspicuous scars. The beds from No. 61 to 

 No. 119 of Mr. C. occupy the face of a precipice, the middle of which is in- 

 dented by a deep chasm. At the foot of this chasm, just below the crop of 

 No. 1 14, the warm spring bursts out described by Mr. C. as beginning to flow 

 in the montiis of March and April. An old quarry has been worked immedi- 

 ately beyond this chasm. On inspecting the section of the defile it will be 

 seen, that from I he Hotwells to this quarry the strata rise to the north-west at 

 an angle gradually decreasing from 40° to 15° ; and that in the quarry the 

 inclination is even less than 15° ; but that immediately beyond it the less in- 

 clined beds abut against others thrown up at an angle of 70°, and exhibiting a 

 remarkable curvature in the upper part. The limestone cliff" then terminates, 

 and is succeeded by a steep, though not precipitous, bank, in which the strata 

 close to the termination of the cliff" are much confused and contorted. These 

 signs of disturbance mark the occurrence of a great fault, to the north of which 

 the strata have subsided to the depth of at least 130 fathoms, so that in the bank 

 adjoining to the limestone cliff", we have a repetition of the entire series already 

 traced from the fort of Windsor terrace to the Hotwells : viz. of the millstone- 

 grit, of the 4 subdivisions of the upper limestone-shale, and lastly of the upper 

 beds of the great mountain limestone. Of the occurrence of a fault there 

 can be no doubt, since, had there been none, the millstone-grit and the upper 

 beds of limestone-shale observed in the bank, must from their direction have 

 been carried directly through the face of St. Vincent's rocks. The existence 

 of this fault is also confirmed by the great horizontal distance that we find be- 

 tween the millstone-grit of St. Michael's-hill in the higher parts of Bristol to 

 the east of Clifton, and the lower beds of mountain limestone at the western 

 foot of Durdham Down near Westbury. This distance, as measured along a 



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