THE DEVONIAN PERIOD. 
43 
easily studied. The rocks differ very little from those 
in the Silurian age, and are not readily distinguish¬ 
able from them ; but in the fossils we notice a great 
difference. 
In examining the fossils of this period, fishes at 
once attract our attention. There are so many, and 
some are so large, that the age period has been truth¬ 
fully called the age of fishes. You would scarcely 
recognize them, for the fossil fishes do not look very 
much like those of this time. They were covered 
with thick, bony scales (and for this reason they are 
doubtless so well preserved); they had teeth two 
inches long; one has been found in Ohio whose 
head measured six feet across, and whose eyes must 
have been three inches in diameter. They looked 
lopsided, for one side of the tail was large and the 
other small, something like the thrasher sharks of the 
present day. The skeleton consisted entirely of soft 
bones. From the appearance and large teeth of the 
