By the Rev. Canon Jackson, ¥.S.A. 295 
other, like a steep staircase, that they could ever be formed according 
to Mr. Poulett Scrope’s idea, seems to myself a simple impossibility. 
Then how were they formed? In answering the question, just 
recollect the general appearance of the downs. As you now see 
them they are covered with a close green sward which fits very tight, 
and shows to a nicety the shape of the ground on which it grows. 
Suppose for a moment, that just in the same way in which you whip off 
the outer skin of a mushroom, or peel a ripe fig, you could tear away 
at one jerk, the whole green surface of South Wiltshire, what would 
you see? You would find a vast area of dried white mud ; not flat, 
but eaten into bays and hollows and basins, semicircular and circular 
amphitheatres, long combes or inclined planes, sloping most gradually 
and winding their way down from the summit of the hill to the 
level plain below; no sharp angles or projecting points, but all 
sweeping and curving smoothly. These smoothly-curving outlines 
show that they can only have been formed by the action of water 
upon that white mud when in a soft state. And in that soft state 
they were when they were under the sea, which I need not say to 
geological hearers, covered the whole in ages gone by. If you could 
draw off the waters of the Mediterranean, or any other present sea, 
‘you would find as much variety in the surface of the floor of it as 
_ you now find on our present dry land, which was once the floor of 
a sea. There are, in every present sea, under-currents and tides 
flowing in every direction, eating and wearing away hollows and 
basins and slanting combes: exactly as tides and under-currents 
once wore away the sides of those downs, as drawn upon the map 
before you. These chalk hills are composed of Jayers of chalk of a 
few feet thick one upon another, of different quality, some fiuer, 
some coarser, some softer, some harder; and my own belief is, that 
these banks and ridges which you see running up, and down, and 
along, sometimes singly, sometiines in twos or threes, or it may be 
dozens, one upon the other, are simply layers of chalk rather harder 
than the rest, which have resisted the action of the water, whilst. 
the softer portions of them have been washed away. Itis, I believe, 
the opinion of many geologists, that to whatever extent these terraces 
or banks may have been subsequently enlarged, or made more even, 
