144 
Geology of Sydney. 
(4) That no remains of animals likely to have 
produced such impressions are found in these strata, 
except the Labyrinlhodon * 
It will be remembered that we are dealing now 
with the Lower Secondary or Lower Mesozoic rocks, 
and no picture of the life of this period would be com- 
plete without a reference to the extraordinary forms of 
life that characterise the period as disclosed by an ex- 
amination of these rocks in Europe and America. We 
learn from the studies of localities where the Secondary 
rocks have been minutely examined, that at this time 
quite new types of life became introduced to this earth. 
A new cycle begins differing widely from anything 
known in the preceding or Palaeozoic times. So 
decided is this change that Page remarks : c< If the 
Palaeozoic and Mesozoic fossils were arranged on 
opposite sides of a museum the difference would strike 
an observer as would that between the brute-man sculp- 
tures of Nineveh and the man-god of the Greeks and 
Romans.' ” 
The Palaeozoic corals had their septa arranged in 
fours; corals of later date in sixes. The Palaeozoic cham- 
bered shells had plain and simple divisions ; later shells 
have a most intricately folded division. Add to this 
that Palaeozoic fishes had unequally lobed tails, while 
fishes of more recent times have the tail equally lobed or 
