176 THE STORY OF LIFE IN THE SEAS. 



wrapped in the casing of a meteorite, are 

 questions upon which no light has yet been 

 thrown by scientific observation or speculation ; 

 but this can be said, that at a very early period in 

 the history of life upon the earth the simple 

 green plants must have played an important 

 part. It is on the substances that are formed 

 by the activity of this green coloured substance 

 that all plants and animals are directly or in- 

 directly dependent for their food in the present- 

 day economy of Nature, and we are forced to 

 believe that, whatever may have been the form 

 of the earliest living things, Chlorophyll the 

 green coloured substance of plants must have 

 had an extremely ancient origin. 



Now, in the darkness of the ocean depths 

 Chlorophyll does not and cannot - exist ; for it 

 is one of its characteristic features that it is 

 active only in the rays of direct sunlight ; and, 

 therefore, it is extremely improbable that the 

 cradle of the marine Fauna could have been 

 there. We are then left with two alternatives. 

 It must have been either at the bottom of the 

 shallow waters or on the surface of the seas. 



Both of these sites have had their advocates, 

 but the balance of opinion has now turned 

 decidedly in favour of the first of them the 

 shallow waters. It is not easy to explain the 

 reasons for this view without assuming a fairly 

 complete knowledge on the part of the reader of 

 the various forms of life that are found in the 

 sea, but still a few words of explanation may be 

 written to indicate that the view is a reasonable 

 one. 



