i86 THE CHAIN OF LIFE. 



in with its full force in the later Cretaceous, before the end 

 of the reptilian age, and continued onward to the present 

 time. Thus the plant takes precedence of the animal, and 

 the preparation was made for the mammalian life of the 

 Eocene by the introduction of the modern flora in the Cre- 

 taceous period. In like manner it is possible that the great 

 graphite deposits of the Laurentian indicate a vegetation 

 which preceded the swarming marine life of the Cambrian ; 

 and it is also probable that the palaeozoic land flora existed 

 long before the first land animals. Thus the plant, as in 

 the old Mosaic record, ever appears on the day before the 

 animal, in each stage of th^ development of the world. 



In Chapter iv. we traced the history of the old and rich 

 vegetation of the Coal period. But this vegetation con- 

 sisted principally of cryptogams and those lowest phseno- 

 gams, of the pine and cycad groups, which have naked seeds. 

 In the modern flora we may arrange the several groups of 

 plants somewhat naturally, as follows : — 



Series /., Cryptogams : — 



Class J, Tkallophyies, sea-weeds, lichens, fungi. 

 „ 2, AnophyteSf mosses, etc. 

 ,, 3, Acrogens, ferns, lycopods, horsetails. 



Series //., Ph^enogams : — 



Class 4, GymnospermSy pines, cycads, etc. 

 „ 5, EndogenSf palms, grasses, etc. 

 ,, 6, ExogenSj oaks, maples, etc. 



With reference to the history of these groups the record 

 stands as follows :^Jn the palaeozoic age classes 3 and 

 4 culminated, and constituted the great mass of the 

 arboreal vegetation. On entering the Mesozoic, No. 3 



