the coast of Cornwall,
which are believed to be of about the same age as the newer crags,
Messrs. Kendall and Bell were much struck by the absence of the species
characteristic of the latter. The St. Erth fauna led them to believe
that the Arctic Ocean could not then have opened into the Atlantic, but
that a land-communication had existed between Europe and North America,
so as to form a barrier of separation between the two oceans. This again
perfectly harmonises with the views I have expressed, and supports them.

Let us now look a little more closely at the history and the fauna of
the Baltic and the adjoining lakes, in order to gain additional
information as to the geographical changes which have had such lasting
influence on the peninsula of Scandinavia. The Baltic is a shallow sea
covering an area of 184,496 square miles, and its waters are decidedly
brackish. The fauna is a poor one, being too salt for the purely
freshwater species and not salt enough for the typical marine forms. The
absence of some animals which we should expect to find there is one of
the remarkable features about the Baltic, but, on the other hand, some
species occur which are altogether strangers to the fauna. And these,
moreover, are confined to the extreme northern end of the sea. I need
only refer to the Arctic Seal (_Phoca annelata_), which is confined to
the Gulf of Bothnia, and to the four-horned sting-fish (_Cottus
quadricornis_, Fig. 14, p. 178), neither of which occur on the west
coast of Scandinavia. But there are others which point in an equally
unmistakable manner to the former existence of a marine connection
between the Baltic and the southward prolongation of the Arctic
Ocean--known as the White Sea. It is generally admitted now that such a
union between these two seas, viz., the Baltic and the White Sea,
occurred in recent geological times, but opinions differ as to the
duration of this connection. I adhere to the view expressed by Murchison
and others, that the boulder-clay is a marine deposit. I am also
convinced that the Arctic Ocean, as I have already mentioned,
transgressed over the lowlands of Northern Russia at about the time when
the newer crags were being deposited on the east coast of England; that
the same large sea also covered Northern Germany, Denmark, Holland, and
the lowlands of Sweden, and laid down the lower continental boulder-clay
which is spread over such vast tracts of land in those countries. I
shall ha