346 
the vapour when it cannot burst out forcibly lifting up the 
surface. For the land is not produced merely by what is 
brought down by rivers, as the islands called Echinao.es are 
formed by the river Achelous, and the greater part of Egypt 
by the Nile, where, according to Homer, it was a day and a 
night's journey from the island of Pharos; but in some cases 
by the receding of the sea, as, according to the same author, 
was the case with the Circean Isles." . Then again he says, 
“ Land is sometimes formed in a different manner, rising 
suddenly out of the sea, as if nature was compensating earth 
for its losses, restoring at one place what she has swallowed 
np at another."* He gives abundant instances of islands so 
formed. Then he shows that lands are separated by the sea, 
and islands formed, by this means ; while islands are added to 
the mainland by the elevation of their channels. All this is 
unexceptionable geology. It reads like some modern treatise 
on the principles of the science. Like everything ot that 
early time, it was mixed up with fabulous statements, just as 
nearly all modern geology is mixed up with conjectural notions 
equally fabulous ; but, so far as it goes, it indicates a very 
large and successful observation of the changes that atlect the 
earth's surface. ' 
The great amount of attention now drawn to recent tor- 
mations, lends peculiar interest to the observations and rea- 
sonings of these ancient writers. There seems to be no good 
ground for believing that they had thought of penetrating to 
the secret depths of earlier strata, so as to classify the rocks ; 
but we ourselves have been brought up from the depths to the 
surface by the most important controversies ol our time. 
Hence the peculiar relish with which one now.reads the records 
of thought so ancient, and traces the formation and cliaractei 
of that thought, so very much like the ideas which occupy the 
minds of the men of our own day. 
If we endeavour to sum up the knowledge of the ancient 
philosophers, so far as their geology is concerned, I think 
we should regard them as having observed, to a great extent 
successfully, the characteristic changes of the surface of the 
globe — the degradation of higher strata — the consequent for- 
mation of alluvial land — the upheaval of the bed of the sea, 
and of mountain-ranges — the vast alterations connected with 
the phenomena of earthquakes — as well as the aqueous and 
igneous agencies and forces by which these effects are so 
far accounted for. If we compare their collections of minute 
facts with the collections and classifications of these accu- 
* Pliny, ii. 82, 86, and 87. 
