68 THE STEUCTUEE OE THE GULLY, DUEDHAM DOWNS. 
partly by natural and partly by artificial (i.e. trowel and 
hammer) weathering. 
The lower surface of the undermost calcite rock, (5), juts out 
about a foot beyond the Gully Oolite on which it rests, and 
dips downwards a little towards it. It is slickensided down- 
wards and to the north-east. There is no evidence of faulting 
in the Gully Oolite just below this section. A big vertical 
crack there certainly is, but there are no slickensides, and a 
horizon of abundant crinoid stems passes undisturbed across 
the crack. 
Now the question arises — how is this curious assemblage 
to be accounted for ? 
The mass of shale cannot be a E-haetic or Trias dyke, for 
though the bedding above is horizontal, below it is vertical. 
There are no fossils, and the limestone band, which is not 
Gully Oolite, would be unaccounted for. Moreover, there are 
slickensides, and no pebbles. 
Nor can it be due to the local alteration of the Gully Oolite 
by recent weathering, for the shaly series, and especially the 
non-oolitic limestone, would be unaccounted for. 
It is therefore necessary that one should have recourse 
to faulting of the Middle Limestone Shales into the Gully 
Oolite, and the recognition of the limestone band proved this 
to be the true explanation. 
The chief difficulty in the way is the complicated nature 
of the dislocation required. The first suggestion that I 
entertained was that it was due to two faults sloping towards 
one another to form a V or trough. This was negatived by 
the absence of faulting in the Gully Oolite below. My next 
idea was to invoke a curved fault, or perhaps two crossing 
one another at a right angle. There was no evidence to sup- 
port the latter, and the angle of curve in the former would 
have to be extraordinarily acute. Moreover it is clear that 
the bottom of the series of shales rests on a more or less 
