204 EFFECT OF AN INUNDATION ON COSTORPHINE HILL. 
its trace behind. Occasionally the scratches deviate from the general 
direction, but the majority agree in parallelism with each other, and 
with the general direction not only of the scoops and grooves of the 
rock upon which they occur, but also of the ridges and large features 
of the district. The shape of many of the valleys, moreover, is 
exactly similar to that of those we see excavated by water on a sand¬ 
bank in a running brook ; whilst the form and relative position 
of the hills resemble those presented by the residuary portions 
of the same recent sand-banks in which the brook cuts out its little 
furrows. 
In a small map of the immediate neighbourhood of Costorphine 
Hill, on the west of Edinburgh, he gives in detail fifteen examples, 
within a circle of two miles in diameter, each exhibiting both the 
large and small features which indicate the action of water flowing 
with violence along the surface, and carrying large blocks of stone 
along with it, and points out many others in the adjacent country; 
and after showing that it is quite impossible to refer these effects to 
any causes now in action, arrives at the following conclusion. “All 
the diluvian facts in this neighbourhood that have come under my 
observation concur in denoting one inundation, overwhelming the solid 
mass of this district, this inundation being the last catastrophe to 
which it has been exposed.” 
The direction of the current producing these effects in the 
immediate neighbourhood of Edinburgh has been from the west, 
and seems to have been influenced by the local circumstances of the 
hills enclosing the estuary of the Forth; but in the neighbourhood 
