1883-1884.] 257 



prevailing species are plane, and apparently poplar and willow ; 

 the flora as a whole resembling the Cretaceous Dakota flora of 

 America, and the Miocene (?) flora of Greenland. They would, 

 I think, upon plant evidence be regarded as Cretaceous, but if 

 not, then decidedly Miocene. Elsewhere at about the same, as 

 well as a slightly higher horizon, but still below the London 

 clay, a somewhat different flora is to be found, whose affinities 

 are also rather with the American Cretaceous than otherwise. 

 At Bournemouth I have found a very extensive flora whose 

 affinities are with the American Eocene deposits and the 

 Oligocene or Miocene plant beds of the South of France, Austria, 

 Greece, and Italy. At Hordle, I found, when with Mr. Keeping, 

 a few plants resembling those of Reading and the Green- 

 land Miocene, (?) but in the still newer Gurnet Bay beds there 

 seems a reversion to Bournemouth or southern types. Heer 

 would have described the whole of these, as he did the flora of 

 Bovey Tracey, which is on about the same horizon, as Miocene, 

 though stratigraphically, their Eocene age is beyond dispute. 

 At Aix-la-Chapelle, there is a flora which we only believe to be 

 Cretaceous, for it has some characteristics of the Eocene, because 

 it underlies chalk with flints containing Cretaceous fossils. The 

 same thing occurs in America, where thoroughly Eocene or 

 Miocene looking floras underlie thoroughly Cretaceous faunas. 

 Within the last few days Professor Noetling, of Konigsberg, 

 has written to me to say that the marine deposits intercalated 

 among those most Miocene looking plant beds, the amber beds 

 of Prussia, show these latter to be of Eocene age and about 

 contemporaneous with our London clay. 



Much more to the same effect might be added, but there is 

 sufficient to show that attempts to fix the ages of deposits by 

 aid of dicotyledonous plants must for the present fail. We 

 have not yet commenced to appreciate the delicate progressive 

 gradations among the newer fossil floras, and until they are 

 studied in a new and different spirit, all attempts to define the 

 relative ages of formations through them are premature. Their 

 study is all the more difficult as no considerable collections of 



