PALEONTOLOGY 67 



When we turn to the rocks that represent still older 

 periods of the earth's history we do not find nearly as 

 much as we should like in the way of fossils. That 

 there must have been plants, and land plants too, in 

 Cambrian and Silurian times, and probably earlier, is 

 generally agreed, but their nature has not yet been 

 revealed. That the Palaeozoic forests with their highly 

 complex Gymnosperms and great variety of vascular 

 plants are very far from primitive is obvious. Alas, 

 that the plants recorded from the earliest times should 

 as yet reveal very little indeed about the origin of 

 things. 



It is indeed doubtful whether human knowledge will 

 ever get down to the roots of life. In the meantime, for 

 our reconstruction of the ramifications of the branches of 

 the tree of vegetable life, there is no source of facts to 

 be compared to the fossils. 



