79 
Oil comparing these sections, the most noticeable feature is 
the absence in the Haxbv Road section of the marls that form 
so prominent a feature at Strensall. At Haxby Road snnd is 
prominent, and only a few seams of marl are recorded. But 
the nature of the sandstone and the presence of those marl 
partings indicate a lacustrine origin for these beds. The 
inference is that at York we have the shore of the great lake 
that deposited the red and green marls of Strensall. 
Another conclusion of some interest may be drawn from the 
data obtained from these borings. 
At Strensall 55 feet of sands, marls, and Boulder clay, lie 
above the Trias rocks. At York, the Trias rocks are reached at a 
depth of about 70 feet. At Strensall boring, the present 
surface is 65 feet above sea level, at Haxbv Road it is 45 feet. 
Hence the old contour line is now only 10 feet above sea level 
t/ 
at Strensall (which is 29 miles inland^ and is 25 feet helo}r sea 
level at York (41 miles from the coast). Thus the results 
of these borings add to the mass of evidence which goes to 
prove the sinking of our east coast since glacial times. And 
this sinking seems to have been greater at York than at 
Sti ensall. 
The Boulder clay contour also exhibits a point of some 
interest. At York the clay was reached at a depth of 3 feet, 
at Strensall at a depth of 41 feet.' Hence the level at York 
after the deposition of the Boulder clay instead of being .20 
feet below that of Strensall, was 18 feet above it. Indeed it 
may even have been more, for, as we have seen, there is 
evidence that the subsidence at York was gi eater than that at 
Strensall. Hence tlie country around Strensall must have 
formed a basin with a clay bottom, cut off on the south by 
a ridge of boulder clay. In this basin were accumulated the 
waters which formed the lake that deposited the marls and 
clays overlying the Strensall Boulder clay. The presence of 
sand overlying the marls points to heavy floods during the 
drying up of the lake, or perhaps after its disappearance. 
H. M. PLATNAHER 
