EZ THE HISTORY OF CREATION. 
culated animals (spiders and insects) as well as of vertebrate 
animals (amphibious animals, like newts and frogs). In the 
Permian system there occur, in addition to the amphibious 
animals, the more highly-developed reptiles, and, indeed, 
forms nearly related to our lizards (Proterosaurus, ete.). But, 
nevertheless, we may call the primary epoch that of Fishes, 
because these few amphibious animals and reptiles are 
insignificant in comparison with the immense mass of 
paleeozoic fishes.. Just as Fishes predominate over the other 
vertebrate animals, so Ferns, or Filices, predominate among 
the plants of this epoch, and, in fact, real ferns and tree ferns 
(leafed ferns, or Phylopteridz), as well as bamboo ferns 
(Calamophytze) and scaled ferns (Lepidophyte). These 
ferns, which grew on land, formed the chief part of the 
dense palzeolithic island forests, the fossil remains of which 
are preserved to us in the enormously large strata of coal of 
the Carboniferous system, and in the smaller strata of coal of 
the Devonian and Permian systems. We are thus justified 
in calling the primary epoch either the era of Ferns or that 
of Fishes. 
The third great division of the palzontological history 
of development is formed by the secondary epoch, or the 
era of Pine Forests, which is also called the mesolithie or 
mesozoic epoch. It extends from the end of the Permian 
system to the end of the Chalk formation, and is again 
divided into three great periods. The stratified systems de- 
posited during this pericd are, first and lowest, the Triassic 
system, in the middle the Jura system, and at the top the 
Cretaceous system. The average thickness of these three 
systems taken together is much less than that of the pri- 
mary group, and amounts as a whole only to about 15,000 
