96 MODERN IDEAS OF EVOLUTION 



these are supposed, from their mode of occurrence in 

 later deposits, to be results, direct or indirect, of the 

 agency of life ; and if they afforded no traces of 

 organic forms, still their chemical character would 

 convey a presumption of their organic origin. But 

 additional evidence has been obtained in the presence 

 of certain remarkable laminated forms penetrated by 

 microscopic tubes and canals, and which are supposed 

 to be the remains of the calcareous skeletons of 

 humbly-organised animals akin to the simplest of 

 those now living in the sea. Such animals little 

 more than masses of living animal jelly now abound 

 in the waters, and protect themselves by secreting 

 calcareous skeletons, often complex and beautiful and 

 penetrated by pores, through which the soft animal 

 within can send forth minute thread-like extensions 

 of its body, which serve instead of limbs. The 

 ((tfLaurentian fossil known as Eozoon Canadense may 

 have been the skeleton of such an animal ; and if so, 

 it is the oldest living thing that we know. But if 

 really the skeleton or covering of such an animal, 

 Eozoon is larger than any of its successors, and quite 

 as complex as any of them. There is nothing to 

 show that it could have originated from dead matter 

 by any spontaneous action, any more than its modern 

 representatives could do so. There is no evidence 

 of its progress by evolution into any higher form, and 

 the group of animals to which it belongs has con 

 tinued to inhabit the ocean throughout geological 



