158 PARSONS : TRIAS OF THE VALE OF YORK. 
It happens, fortunately for our purpose, that the site of 
the boring at Reedness is just three miles due east, as the 
crow flies, from Old Goole, and the surface-level may be 
taken as the same at the two places. If, therefore, we find 
that the upper surface of the Bunter is reached at Old Goole 
at 60 feet, and at Reedness at 342 feet, i.e., 282 feet lower, 
an exceedingly simple calculation will prove that the dip (in 
the absence of faults) must be 94 feet per mile, or 1 in 56 ; 
this is equal to an angle of 1° to the horizon. Assuming the 
dip to be the same east of Reedness and west of Goole, as 
between those places, we can calculate the thickness of the 
strata. From Goole to the hills east of the Trent, where the 
lias comes out above the Keuper, is 7 J miles in a direct line ; 
this would give 7 J X 94 = about 700 feet as the thickness 
of the Keuper. In the same way, the breadth of the belt of 
Bunter, from Goole to the magnesian limestone hills about 
Knottingley, being 13 \ miles, the thickness of the Bunter 
will be 1,270 feet. This is considerably greater than that 
given in the sections of the Geological Survey, which show it 
to be only 500 feet ; but that this thickness is under 
estimated, is shown by the fact that the Reedness borings 
penetrated the Bunter for 689 feet, and those at New Bridge, 
five miles west of the edge, for 500 feet, without reaching the 
bottom. 
The Bunter is exposed about Tickhill, Doncaster, and 
Finningly, and other patches occur at Barney Bon, Hatfield, 
Wroot, and Thorne. A low ridge extends nine miles east 
and west from Cowick to Kellington, and is prolonged 
eastwards under the alluvial strata to Rawcliffe and Goole. 
There are also detached patches at Whitley, and another 
north of the Aire at Carlton and Camblesforth. West of 
Selby it rises into two hills, Bray ton Barf (175 feet) and 
Hambleton Haugh (150 feet). It is struck in borings at 
Sandtoft, Goole, Rawcliffe, Temple Hirst, Selby, Osgodby, 
