a marina_ abounds on a series of sand banks, partially
uncovered by the larger stream tides, which lie directly opposite the
town of Cromarty, near the spot pointed out by tradition as the site of
an earlier town, which was swept away some two or three hundred years
ago by the encroachments of the sea. And these banks, with their thick
covering of green Zostera, used to be pointed out by the fishermen of
the place, in my younger days, as the _meadows_ of the old town, still
bearing their original coverings of vegetation,--a vegetation altered no
doubt by the "sea change" that had come over it, but still essentially
the same, it was said, as that which had smiled around the old burgh,
and not at all akin to the brown kelp or tangle that every storm from
the boisterous north-east heaps along the shore. It was virtually
affirmed that the luxuriant terrestrial grasses of ancient Cromarty had
made a virtue of necessity in their altered circumstances; and that,
settling down into grasses of the sea, they remained to testify that an
ancient Cromarty there had _once been_. _Zostera marina_, like most
plants of the land, ripens its seeds towards the close of autumn; and I
have seen a smart night's frost at this season, when coincident with a
stream tide that laid bare the beds, nip its seed-bearing stems by
thousands; and have found them strewed along the beach a few days after,
with all their grass-like spikes fully developed, and their grain-like
seeds charged with a farinaceous substance, which one would scarce
expect to find developed in the sea. In the higher reaches of the
Cromarty Firth, the Zostera beds, which are of great extent, are much
frequented, during the more protracted frosts of a severe winter, by
wild geese and swans, that dig up and feed upon the saccharine roots of
the plant. The Zostera of the warmer latitudes attain to a larger size
than those of our Scottish seas. "A southern species," says Loudon,
"_Zostera oceanica_, has leaves a foot long and an inch broad. It is
used as a thatch, which is said to last a century; bleaches white with
exposure; and furnishes the rush-like material from which the envelops
of Italian liquor flasks are prepared." The simple rectilinear venation
of ribbon-like fronds, usually much broken, that occurs in the Lower Old
Red Sandstone, has often reminded me of that exhibited by this exotic
species of Zostera.]

[Illustration: Fig. 118.

FUCOID.]

[Illustration: Fig. 119.

F