54 
THE SILURIAN BEACH. 
tion of the geological record, filling up the sup- 
posed lapses to suit themselves, more cautious as 
to their results. 
We have found, then, Radiates, Mollusks, and 
Articulates in plenty ; and now what is to be said 
of Vertebrates in these old times, — of the high- 
est and most important division of the Animal 
Kingdom, that to which we ourselves belong ? 
They were represented by Fishes alone ; and the 
Fish chapter in the history of the early organic 
world is a curious, and, as it seems to me, a very 
significant one. We shall find no perfect speci- 
mens ; and he would be a daring, not to say a 
presumptuous thinker, who would venture to re- 
construct a fish of the Silurian age from any 
remains that are left to us. But still we find 
enough to indicate clearly the style of those old 
fishes, and to show, by comparison with the living 
types, to what group of modern times they be- 
long. We should naturally expect to find the 
Vertebrates introduced in their simplest form; 
but this is by no means the case : the common 
fishes, as Cod, Herring, Mackerel, and the like, 
were unknown in those days. 
But there are two groups of so-called fishes, 
differing from these by some marked features, 
among which we may find the modern represent- 
atives of these earliest Vertebrates. Of these 
two groups one consists chiefly now of the Gar- 
