188 
CARBONIFEROUS LIMESTONE SERIES. 
ravine traversing Leigh Down at Sir A. Elton's Park.i After passing the 
limestone, which bounds the ravine towards the south, the sides abruptly 
change to the Pennant coal-grit, full of coaly matter dipping south- 
ward, m the same direction as the limestone, and apparently beneath 
it- • • • To the east of the ravine the coal-grit occupies the 
escarpment of Leigh Down for the space of 4 miles, as far as the coal 
mines of Clapton, beyond which it is concealed beneath the marshy 
plain. In this interval the stratification of the coal-measures is very 
much disturbed, but their general dip is southerly, towards the fault." 
Mr. F. Dixey, on the other hand, in the paper referred to 
above, regards the line of junction of the Coal Measures and older 
rocks S. of Clapton as an unconformable one. He says 2 : — 
" In the neighbourhood of Clapton in Gordano the southern boundary 
of the Coal Measures transgresses the outcrop of the Carboniferous Lime- 
stone, the Lower Limestone Shale, and the Old Red Sandstone, and 
the Coal Measures enclose several small patches of Carboniferous 
Limestone. Moreover, whereas the Lower Carboniferous and older 
strata possess a variable but persistent southern dip, the Coal Measures 
dip to the north and north-west." 
While there can be no doubt that Vaughan was right 
in considering that the Coal Measures in relation to the isolated 
patches of Carboniferous Limestone near Clapton rest directly 
on the limestone, the Coal Measures certainly have not always 
a northerly or north westerly dip. In the best exposure, that 
of Conygar quarry the dip is 25 0 S.E. and at Clevedon 
Cottages 30 0 S.E., in each case if no fault intervened the 
Coal Measures would pass below the Carboniferous Limestone, 
which lies not many yards away to the S. Further to the E. the 
relations are less clear and the dips vary, but Buckland and 
Conybeare's statement (p. 239) that while the strata are very 
much disturbed the general dip of the Coal Measures is southerly 
is probably correct. Hence I agree with Buckland and 
Conybeare, with Prof. Lloyd Morgan, and the Geological 
Surveyors as to the faulted character of the Carboniferous Lime- 
stone boundary to the W. of Nash House. 
The Observatory Hill Fault. — The reversed fault of 
Observatory Hill, Clifton has been described by many geologists, 
the latest being Prof. Lloyd Morgan 3 and Dr. Vaughan. 4 Its 
most remarkable feature is the rapidity with which it dies out 
when followed N.W. Prof. Lloyd Morgan's map shows it 
extending as far as the Old Red Sandstone of Failand. I am 
inclined to think it dies out somewhat sooner than this, and to 
trace its course somewhat to the S. of Prof. Lloyd Morgan's line. 
After leaving Leigh Woods, where it does not follow Nightingale 
Valley but passes well within the limits of Stokeleigh Camp, the 
fault crosses the road somewhat to the S. of Beggar's Bush 
1 i.e. , that between Strawberry Hill and Court Hill, Clevedon. 
2 P- 3 I 3- 
3Proc. Bristol Nat. Soc, n.s., Vol. IV. (1884), pp. 185-189 and Q.J.G.S., 
Vol. XLI. (1885), pp. 146-151. 
4B.N.S. Paper, p. 88. 
