PALAEONTOLOGY 61 



be associated with impressions which show the external 

 form of the plant till we have a fair idea what it was 

 like both inside and out. From these data we can 

 do something to deduce the ecological condition under 

 which it grew. This again leads us on to consider 

 such data as indicators of the climates of the departed 

 continents. Hence we see that the field that is opened 

 up by fossil botany is a very extensive one. 



This branch of the science is, indeed, only in its 

 infancy, but it has obtained some results of great interest. 

 One or two of them we should now consider. 



Without recapitulating the elements of geology, it 

 is well, perhaps, to point out that the epochs of the 

 world's history, since the deposition of the sedimentary 

 rocks began, have been found to be characterised by 

 different series of dominant animals first, the lower 

 invertebrates, then the simple vertebrates, such as 

 fishes, then the higher in the scale, up to the mammals, 

 and, lastly, in very recent times (speaking geologically) 

 man himself. The history of the plant world seems 

 to be expressed in a similar series, and, on the whole, 

 there is a wonderful agreement in result between the 

 study of the plant and animal fossils. 



If we begin our study of the botany of the past at 

 the end nearest the present, then the first really im- 

 portant point to notice is that in comparatively recent 

 times in England, in the middle and lower Tertiary 

 rocks, for instance, there must have been a rather 

 different climate from the present, for we find remains 

 of Palms and other semi-tropical plants in these isles. 



We do not have to go very far back in the history of 

 the whole earth to come to the time when none of the 

 higher plants were living at all. All the members of 

 the huge and important group of Angiosperms are of 



