70 THE EAKTH. 



five or six feet long, called the " Labyrinthodon " (fig. 20). 



PIG. 20. LABYRINTHODON. 



The oxide of iron, or some other agent appears to have pre- 

 vented the fossilisation of the inhabitants of these strata, for 



FIG. 21 IMPRESSIONS OP FEET IN NEW RED SANDSTONE. 



but few of their organic remains have been preserved ; but 

 very curious evidences of their existence nevertheless remain, 



