68 THE DAWN OF LIFE. afl 



examples from the beds holding Eozoon at St. Pierre, 

 on the Ottawa. They occur at this place on the sur- 

 face of layers of the limestone in vast numbers, as if 

 they had been growing separately on the bottom, or 

 had been drifted over it by currents. These we shall 

 further discuss hereafter. Such was the general mode 

 of growth of Eozoon, and we may now consider more in 

 detail some questions as to its gigantic size, its precise 

 mode of nutrition, the arrangement of its parts, its rela- 

 tions to more modern forms, and the effects of its growth 

 in the Laurentian seas. In the meantime a study of 

 our illustration, Plate IV., which is intended as a magni- 

 fied restoration of the animal, will enable the reader 

 distinctly to understand its structure and probable 

 mode of growth, and to avail himself intelligently of 

 the partial representations of its fossilised remains in 

 the other plates and woodcuts. 



With respect to its size, we shall find in a subsequent 

 chapter that this was rivalled by some succeeding 

 animals of the same humble type in the Silurian age ; 

 and that, as a whole, foraminiferal animals have been 

 diminishing in size in the lapse of geological time. It 

 is indeed a fact of so frequent occurrence that it may 

 almost be regarded as a law of the introduction of new 

 forms of life, that they assume in their early history 

 gigantic dimensions, and are afterwards continued by 

 less magnificent species. The relations of this to ex- 

 ternal conditions, in the case of higher animals, are often 

 complex and difficult to understand ; but in organisms 

 so low as Eozoon and its allies, they lie more on the 



