2 
INTRODUCTION. 
each of which is distinguishable not only by the different character of material composing it, 
but also by fossil remains found therein, which afford a means for proximately determining the 
time required in their formation. These several layers may be likened to the figures on the dial of a 
clock, since they serve to mark the time, or rather epochs, or eras, in the earth’s existence, and to 
each is therefore given a name to indicate the infinitely great periods that have elapsed since God’s 
hand began the work of fashioning the world. 
These general divisions are again subdivided, just as the hours on the clock are divided into 
minutes, in order that the measurements of time may be more exactly reckoned. The general 
divisions, arranged in their regular order, are known by the following scientific names, viz.: The 
Archaean (meaning beginning) the Palaeozoic (ancient life), the Mesozoic (middle life), and the 
Neozoic (new life). The subdivisions of these general groups are represented in the following table • 
Mr. Hinman has made 
another division, in which 
the special and characteristic 
fossils of each period are 
given, as also the relative 
time occupied, so to speak, 
by each epoch, but in which 
the orders are reversed; that 
is, on a descending scale, in¬ 
stead of an ascending table, 
as I have given above. This 
order has been heretofore in¬ 
variably observed by writers 
on geology and natural his¬ 
tory, though it is manifestly 
improper when applied to the 
latter, since all nature proceeds upon an ascending scale. His arangement is as follows : 
In the oldest, or Arch^an stra¬ 
tum, no fossil remains have been found, 
though this fact does not necessarily 
imply that there was no animgl life on 
our globe during that period. The 
inconceivably great time that has . 
elapsed, the immense superposition 
of stratum on stratum, and parti¬ 
cularly the metamorphosis that the 
strata have undergone by the action 
of fire, would have destroyed any 
trace of fossil remains, however nu¬ 
merous they may have been. But 
the absence of all fossils ‘ ‘ prevents 
us from determining the relative ages 
of the different parts of this group,” 
as Hinman observes. 
The Paleozoic Era, on the 
other hand, is distinguished for the abundance of animal and vegetable life that then existed, 
though it was in this period that these evidences of abounding life first appeared. This primary 
animal life, however, was all of the simplest, I might say almost rudimentary, forms, so low in 
the scale as scarcely to be distinguishable from the vegetable. Representatives still survive in 
the protozoanid.ee, as will be found explained in this work. 
PRIMARY OR PALEOZOIC 
SECOND- 
TERTIARY 
Relative 
length 
of various 
Geological 
Periods 
> 
I 
> 
z 
CAMBRIAN 
SILURIAN 
DEVONIAN 
CARBONIFEROUS 
s 
k 
1 
-«£ 
»> 
CRETACE0U8 
EOCENE 
2 
§ 
m 
PLIOCENE | 
SEA 
VE 
ED 
THALLOGENS 
PLANTS 
Relative age of various groups 
RNS 
ACROGENS 
F 
E! 
PALM 
8 
(gymnosperms 
s 
(. ANGIOSPERMS 
\ 
( 
:onif 
•RS 
jlLMS 
i 
iALYX 
CORO 
LLA 
LOWER GROUPS 
_incl.arthropoda 
ANIMALS 
FISHES 
REPTILES 
MAMMALS 
— MAN 
ERAS OF TIME—CORRESPONDING TO HOURS. 
PERIODS OF TIME—CORRESPONDING TO MINUTES. 
Archaean, 
f Laurentian 
, \ Huronian 
Paleozoic,. 
f Cambrian 
| Lower Silurian 
1 | Upper Silurian 
| Devonian 
[ Carboniferous 4 
Mesozoic,. 
f Permian 
1 Triassic 
) Jurassic 
[ Cretaceous 
Neozoic,. i 
i 
f Tertiary 
\ Quaternary 
