118 EVOLUTION OF ZI. 
so striking a feature of the Carboniferous, is to be noticed 
as an important fact for the Evolutionist, the Cycadæ and 
Coniferee completely replacing them. Among the Batrachia 
of the Trias are to be noticed the immense Labyrinthodons, 
the skull in one species measuring three feet long by two 
wide; remains of these animals have been found near 
Gwynedd, in the Triassic of Pennsylvania. The Connecticut 
Sandstone is famous for its tracks, supposed to have been 
made by large Reptiles, of which more than fifty species 
have been described. During this period the Birds first 
appeared, and, from their tracks left in the sandstone, they 
are thought to have resembled the Running-birds of the 
present day, though much larger, the Brontozoon (Fig. 148) 
of the Connecticut valley being four times as large as the 
Ostrich. The existence of'such large birds may be doubted 
by those who are not familiar with fossils. Those, however, 
who have seen the gigantic Dinornis of the British Museum 
— 
are quite satisfied with Prof. Owen’s statement, that they . 
é« 
are "equal to the formation of tridactyle impressions as 
large as those of the Connecticut Sandstones.” (Tal PD. T) 
In the Triassic the remains of Mammals are first found. 
The fossil remains Microlestes and Dromatherium (Fig. 
149) are usually regarded as Marsupials, or pouch-bearing 
Mammalia. The Dromatherium, according to Prof. Owen, 
“would appear to find its nearest analogue in the Myrme- 
cobius,” a little Marsupial living at the present day in 
Australia. These fossil Mammals have been supposed by 
some authors to be Monotremata, though that order have 
no teeth, as in the Duck-bill, etc. This perhaps, however, 
was not the primitive condition of the order, the first 
Monotremata having teeth, which their descendants have 
lost through 'adaptation to their peculiar mode of life. 
Whether this view be or be not confirmed by future 
research, the important fact to be noticed is that in either 
case the Mammals which first appeared on the earth were 
