[Illustration: A FLOWERY BANK NEAR COOKHAM. _From a photograph by E.
Seeley_.]

The things in the waters and growing out of the waters are very, very old.
The mountains have been burnt with fire; lava grown solid has turned to
earth again and grows vines; chalk was once sea-shells; but the clouds and
the rivers have altered not their substance. Also, so far as this planet
goes, many of the water plants are world-encircling, growing just as they
do here in the rivers of Siberia, in China, in Canada, and almost up to
the Arctic Circle. The creatures which lived on these prehistoric plants
live on them now, and in exactly the same parts of the stream. The same
shells lie next the banks in the shallows as lie next the bank of the
prehistoric river of two million years ago whose bed is cut through at
Hordwell Cliffs on the Solent. The same shells lie next them in the deeper
water, and the sedges and rushes are as "prehistoric" as any plant can
well be. In the clay at Hordwell, which was once the mud of the river, lie
sedges, pressed and dried as if in the leaves of a book, almost exactly
similar in colour, which is kept, and in shape, which is uninjured, to
those which fringe the banks of the Thames to-day. These fresh-water
plants show their hoary antiquity by the fashion of their generation. Most
of them are mono-cotyledonous--with a single seed-lobe, like those of the
early world. There is nothing quite as old among the Thames fishes as the
mud fishes, the lineal descendants of the earliest of their race. But the
same water creatures were feeding on the same plants perhaps when the
Thames first flowed as a river.

[Illustration: BURR REED AND FLOWERING RUSH. _From photographs by E.
Seeley._]