118 LIFE ON THE EARTH. 



high a grade of organization in Megalosaurus and 

 Iguanodon as the aquatic Crocodilians, of the same 

 ages, Teleosaurus, Steneosaurus, Cetiosaurus and their 

 allies. The earliest traces of Land Saurians are those 

 already alluded to as found in the Nova Scotia coal- 

 field, one of which is supposed to be of Lacertian, 

 the other of Ganocephalic affinity. Perhaps in re- 

 gard to most of the Saurian fossils we may prudently 

 wait for further information before confidently as- 

 signing them to marine, fluviatile, or terrestrial life. 

 Ichthyosaurus is no doubt truly marine, Megalo- 

 saurus truly terrestrial; regarding many others we 

 may reserve an opinion. 



Of fossil birds our evidence is mostly in footsteps, 

 sometimes, as in Connecticut 1 and near Hastings 2 , 

 of such extraordinary magnitude as to match the 

 stride of the Moa of New Zealand. In general the 

 footprints are of the Cursorial order of Birds ; marks 

 of their movements are found in the sandy shores 

 of the Permian, Triassic, and Oolitic Seas. 



Mammalia of the Marsupial order appear to have 

 the priority in time. The most ancient fossils of 

 this kind yet traced are the small insectivorous 

 teeth found in the Trias of Wurtemburg 3 . Next 



1 Hitchcock, Mem. American Academy ', Vol. m. 

 8 Beckles, Journal of Geol. Soc. 

 3 Lyell, Elem. of Geol. p. 343. 



