LAMPLUGH : NOTES ON THE WHITE CHALK OF YORKSHIRE. 
73 
a precipice 270 feet in height, consisting entirely of Flinty Chalk, 
with an inconsiderable covering of glacial deposits. The dip is still 
southward, at an angle of under 5*, and as the trend of the cliff in 
this neighbourhood is west-north-west, a slow rise of the strata is 
presented, apparently nearly corresponding with the rise of the 
ground. Hence in the section at Gull Nook it is probable that the 
beds which form the headlands at Thornwick are still present. 
Beyond this point the cliffs continue for one mile farther of about 
the same height and general tendency, until Old Dor is reached, 
where the strata are plunged suddenly in violent contortions, magnifi- 
cently displayed in a slightly overhanging precipice 290 feet deep. 
This fine section was illustrated by a series of photographs issued by 
the Society in 1885, accompanied by a short descriptive article from 
the pen of our lamented Secretary, the late Mr. J. W. Davis. 
The contortions continue for about 200 3^ards and then as 
suddenly cease. To estimate and eliminate the effect of this dis- 
turbance in measuring the Chalk is an exceedingly difficult problem. 
I have thrice reached the spot from below ; but these visits were all 
hurried, and they failed to give me any clue. I could not identify 
any particular band amid the maze-like twistiugs ; and although 
there are several small fractures crossing the strata, I could not see 
any clear indications of faulting. It is indeed highly probable that 
there is a fault at this place, but so far as one can judge the 
displacement is not likely to be large. If the fault ran inland across 
the strike and its throw were considerable in either direction, it 
would, in the interior, shift the boundary between the Flinty Chalk 
and the Chalk-without-fiints, and I have traced this boundary at 
intervals fromFlamborough toSpeeton \nthout detecting any important 
break. There is still, of course, the possibility of the fault being in 
the direction of the strike, and so remaining wholly within the Flinty 
Chalk in this area ; and I am indeed inclined to believe that a dis- 
placement of this character does exist in the Bempton Valley ; but, 
even if this be the case, its dimensions cannot be large. On the 
whole, therefore, I think we may disregard this disturbance without 
vitiating our results. I suspect that its general effect is to slightly 
carry down the base of the Flinty Chalk on the north-western side of 
