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county, which was suddenly exposed to view by the shifting 
of a sand bank. In South Wales, Giraldus de Barri, or 
Cambrensis, as he is usually termed, observed such a 
phenomenon so long ago as 1188. He says in his 
" Itinerary," chapter 13, page 217, " The sandy shores of 
South Wales being laid bare by the extraordinary violence 
of a storm, the surface of the earth which had been covered 
for many ages re-appeared, and discovered the trunks of 
trees cut off, standing in the very sea itself, the strokes of 
the hatchet appearing as if made only yesterday ; the soil 
was very black, and the wood like ebony. By a wonderful 
revolution, the road for ships became impassable, and looked 
not like a shore, but like a grove, cut down perhaps at the 
time of the deluge, or not long after, but certainly in very 
remote times." In my opinion, however, these, and many 
other instances that might have been mentioned, of the 
present position of what have clearly once formed large 
forests districts, but are now far below the usual level of the 
sea, can only be satisfactorily accounted for by partial 
subsidences of the crust of the earth. This theory may 
indeed appear to be more marvellous than the preceding 
ones, and therefore less likely to be true in the opinion of 
those who are acquainted with geology ; but when from the 
study of that science we find that certain strata, the 
undoubted deposit of water, are now upheaved far above the 
reach of that element, and that large tracts of land have 
sunk beneath it, we can only regard such changes as one 
of the usual, but always wonderful, operations of nature. 
Strabo was well acquainted with this motive power in the 
earth's crust, who says, 4 4 It is not because the lands covered 
by seas were originally at different altitudes that the waters 
have risen or subsided, or receded from some parts and 
inundated others ; but the reason is that the land is some- 
times raised up, and sometimes depressed, and the sea also 
