246 THE OLD RED SANDSTONE. 
parasitical shells and zoophytes— proof that the creature, 
having attained its full size, has ceased to cast its plated cov- 
ering. Crustaceans of the smaller varieties abound. Her- 
mit crabs traverse the pools, or creep among the weed; the 
dark green and the dingy, hump-backed crabs occur nearly 
as frequently; the radiata cover the banks by thousands. 
We find occasionally the remains of dead fish left by the re- 
treating tide; but the living are much more numerous than 
the dead ; for the sand-eel has suffered the water to retire, 
and yet remained behind in its burrow ; and the viviparous 
blenny and common gunnel still shelter beside their fuci- 
covered masses of rock. Imagine the bottom of this little bay 
covered up by thick beds of sand and gravel, and the whole 
consolidated into stone, and we have in it all the conditions 
of the deposit of Balruddery —a mud-colored, arenaceous 
deposit, abounding in vegetable impressions, and enclosing 
numerous remains of crustaceans, fish, and radiata, as its 
characteristic organisms of the animal kingdom. There 
would be but one circumstance of difference: the little bay 
abounds in shells ; whereas no shells have yet been found in 
the mudstones of Balruddery, or the gray sandstones of 
the same formation, which in Forfar, Fife, and Moray shires 
represent the Cornstone division of the system. 
Ages and centuries passed, but who can sum up their num- 
ber? In England, the depth of this middle formation greatly 
exceeds that of any of the other two; in Scotland, it is much 
less amply developed; but in either country it must rep- 
resent periods of scarce conceivable extent. I have listened 
to the controversies of opposite schools of geologists, who, 
from the earth’s strata, extract registers of the earth’s age of 
an amount amazingly different. One class, regarding the 
geological field as if under the influence of those principles 
