THE MESOZOIC AGES. 201 



comparable in value and thickness to those of the old 

 coal formation. Of this kind are the coal beds of 

 Brora in Sutherlandshire, those of Richmond in 

 Virginia, and Deep River in N. Carolina, those of 

 Vancouver's Island, and a large part of those of 

 China. To the same age have been referred some at 

 least of the coal beds of Australia and India. So 

 important are these beds in China, that had geology 

 originated in that country, the Mesozoic might have 

 been our age of coal. 



If the forests of the Mesozoic present a great 

 advance over those of the Palaeozoic, so do the 

 animals of the land, which now embrace all the great 

 types of vertebrate life. Some of these creatures 

 have left strange evidence of their existence in their 

 footprints on the sand and clay, now cemented into 

 beds of hard rock excavated by the quarryman. If 

 we had landed on some wide muddy Mesozoic shore, 

 we might have found it marked in all directions with 

 animal footprints. Some of these are shaped much 

 like a human hand. The creature that made this 

 mark was a gigantic successor of the crocodilian 

 newts or labyrinthodonts of the Carboniferous, and 

 this type seems to have attained its maximum in this 

 period, where one species, Labyrinth odon giganteus, 

 had great teeth three or four inches in length, and 

 presenting in their cross section the most complicated 

 foldings of enamel imaginable. But we may see on 

 the shores still more remarkable footprints. They 

 indicate biped and three-toed animals of gigantic 



