IMIOGRESS OF ANIMAL LIFE. 1 lo 
the lower classes prevailed chiefly at the com- 
encement of organic life, but they did not 
prevail we find in rocks of the tran- 
1 ion oimation, not only remains of radiated 
r animals and mollusks, such as 
Jert Nautili; but we see the 
vertebrata also represented by the Class of Fishes. 
strau! easiest 
strata of the secondary formations.* In the foot- 
Stepan .he New Red sandstone, we have “I 
.ably the first traces of Birds and Marsupialia 
(See PI ib-. and 2tS.) The bones of Birds occur 
hose of Marsuptalta m the Oolite at Stonesfleld. 
of lb i'®*' ‘"‘‘•"'dy regions 
f the secondary strata, are the earliest remains 
yet discovered of Cetacea-f In the tertiary forma- 
Mamrii!”'' “<> ‘^‘rial 
Mammalia, some referrible to existing genera 
d all to existing orders. See PI. l, fig. jl-ioi’ 
ot animals become gradually more abundant as 
' e advance from the older into the newer series 
^ gh often changed in genus and species, and 
near Bristol*' Magnesian Conglomerate of Durdham Down 
of Mansfeld’irthe *^^"P'’o‘'®oli>efer) 
OoSitloTEn.’.’" Museum, an ulna from the Great 
f'y Cuvier and°**^ Mtoodstock, Oxon, which was examined 
of a very I’arrre cetaceous ; and also a portion 
y argc nb, apparently of a whale, from the same locality. 
