-128 THE DAWN OF LIFE. 



the group Protozoa, of gigantic size and comprehen- 

 sive type, and oceanic in its habitat, is as likely as 

 any other creature that can be imagined to have been 

 the first representative of animal life on our planet. 

 Vegetable life may have preceded it, nay probably did 

 so by at least one great creative geon, and may have 

 accumulated previous stores of organic matter ; but if 

 any older forms of animal life existed, it is certain at 

 least that they cannot have belonged to much simpler 

 or more comprehensive types. It is also to be ob- 

 served that such forms of life, if they did exist, may 

 have been naked protozoa, which may have left no 

 sign of their existence except a minute trace of car- 

 bonaceous matter, and perhaps not even this. 



But if we do not know, and perhaps we are not 

 likely to know, any animals older than Eozoon, may 

 we not find traces of some of its contemporaries, 

 either in the Eozoon limestones themselves, or other 

 rocks associated with them ? Here we must admit 

 that a deep sea Foraminiferal limestone may give a 

 very imperfect indication of the fauna of its time. A 

 dredger who should have no other information as to 

 the existing population of the world, except what he 

 could gather from the deposits formed under several 

 hundred fathoms of water, would necessarily have very 

 inadequate conceptions of the matter. In like manner 

 a geologist who should have no other information as 

 to the animal life of the Mesozoic ages than that fur- 

 nished by some of the thick beds of white chalk 

 might imagine that he had reached a period when the 



