I9I4-] SOUTHEASTERN NORTH AMERICA. 143 



legitimate method until negatived in human experience. If it be 

 assumed untrue there is no limit to idle speculations as futile as those 

 of medieval times. 



The Wilcox flora as described in the present study comprises con- 

 siderably more than 300 species — the exact number is without sig- 

 nificance since it is so largely dependant on accidents of preservation 

 and discovery, and since it is also considerably influenced by the 

 evaluation of specific characters. The number might readily be 

 increased to 400 if fragments of new forms were considered the 

 basis for the description of species. 



This flora is therefore one of the largest floras as yet known from 

 a single geologic horizon in a single area, although it is considerably 

 overshadowed numerically by the so-called Fort Union flora of the 

 Rocky Mountain Province, which however covers a greater geo- 

 graphic area and a longer interval of time. 



Compared with foreign Eocene floras of similar age it may be 

 noted that Ettingshausen enumerated 72 genera and 200 species from 

 the London Clay of the Island of Sheppey 7 and 116 genera and 274 

 species from Alum Bay on the Isle of Wight. 8 I mention these two 

 English floras specifically since while never adequately described 

 they are at least partly contemporaneous with that of the Wilcox, as 

 I hope to show in the chapter on correlation, and they therefore offer 

 various interesting details for comparison as will appear on subse- 

 quent pages. 



The Wilcox flora comprises 128 genera in 59 families and 33 

 orders. The Thallophyta are represented by a few species of leaf- 

 spot fungi, and if the student were to follow the fashion set by the 

 older continental paleobotanists the so-called species of spot-fungi 

 could be increased many fold, as I have only picked out for enumer- 

 ation certain conspicuous or characteristic types. The Bryophyta, 

 as is usually the case in fossil floras, are entirely unrepresented, al- 

 though the sediments are often of a character to have preserved them 

 in perfection if they had been present, and the assumption is logical 

 that they were either confined to more northern latitudes at this time 

 or were an exceedingly minor element in the flora. The Pterido- 



7 Ettingshausen, Proc. Roy. Soc. Loud., Vol. 29, 1879, PP- 388-396. 



8 Ettingshausen, Ibidem, Vol. 30, 1880, pp. 228-236. 



