THE OLD RED SANDSTONE. 93 
‘of wood tnat have been borne out to sea by the gulf stream 
from the shores of Mexico or the West Indian Islands, strand. 
ed on the rocky coasts of Orkney and Shetland.* 
The dissimilarity which obtains between the fossils of the 
contemporary formations of this system in England and Scot- 
land, is instructive. The group in the one consists mainly of 
molluscous animals ; in the other, almost entirely of ichthy- 
olites, and what seems to have been alge. Other localities 
may present us with yet different groups of the same period 
—with the productions of its coasts, its lakes, and its rivers. 
At present, we are but beginning to know just a little of its 
littoral shells, and of the fish of its profounder depths. These 
last are surely curious subjects of inquiry. We cannot catechise 
our stony ichthyolites, as the necromantic lady of the Arabian 
Nights did the colored fish of the lake, which had once been 
a city, when she touched their dead bodies with her wand, and 
they straightway raised their heads and replied to her queries. 
We would have many a question to ask them if we could — 
questions never to be solved. But even the contemplation of 
their remains is a powerful stimulant to thought. ‘The won- 
ders of Geology exercise every faculty of the mind— reason, 
memory, imagination; and though we cannot put our fos- 
sils to the question, it is something to be so aroused as to 
be made to put questions to one’s self. I have referred to 
the consistency of style which obtained among these ancient 
fishes —the unity of character which marked every scale, 
plate, and fin of every various family, and which distin- 
guished it from the rest; and who can doubt that the same 
shades of variety existed in their habits and their instincts ? 
We speak of the infinity of Deity —of his inexhaustible va- 
riety of mind; but we speak of it until the idea becomes a 
piece of mere commonplace in our mouths. It is well to be 
10 * See Note E. 
