COKRELATION. 



151 



whole of the Eastern Hemisphere except Eu- 

 rope has not yet furnished any comparative 

 fossil materiiJ, so that at least threc-fourtlis of 

 the present land surface of the cartii must yield 

 its fossil plant materiid hefore questions of ori- 

 gin and migration can be discussed with any 

 approacli to finality. There are some known 

 Eocene floras in European Russia, and the Ter- 

 tiary floras of Manchuria, Sakhalin, and else- 

 where in eastern Asia ofl'er points of compari- 

 son with the Fort Union flora of the interior 

 region of the United States and the Kenai flora 

 of iVlaska. Engelhardt has also made known 

 some most interesting Tertiary floras from 

 South iVmerica. A discussion of North Amer- 

 ican Eocene floras needs a moi-e complete 

 knowledge of the Eocene paleobotany of Asia 

 and South America. 



No riclily fossilif erous European plant horizons 

 exactly equivalent to the Wilcox have as yet 

 received monographic study. The Eocene of 

 the south of England is rich in fossil plants at 

 horizons that I consider equiv.iJent to the Wil- 

 cox, but comparisons are unfortunately limited 

 to the long lists of noniina nuda published by 

 Ettingshausen, to which I will have occasion to 

 refer in detail. It thus happens that the ex- 

 haustively studied wSannoisian floras of Pro- 

 vence and the Tyrol, so eft'ectively mono- 

 graphed by Saporta and Ettingshausen ro- 

 spectiveh^, although considerably j'ounger, 

 have afl'orded many more elements for com- 

 parison witli the Wilcox than the Eocene flora 

 of England. 



The early Eocene of Europe (Montian and 

 Thanetian stages) includes .small floras in 

 England, Belgium, and France, the most exten- 

 sive being the flora of the marnes heersiennes in 

 Belgian Limburg, southeast of St. Trond, on the 

 road to Liege, so elaborately described by Sa- 

 porta and Marion; that of the travertines of 

 Sezanne on the shore of the old lake of Hilly 

 east of Paris, monographed by Saporta; tiiat 

 of the Trieu de Leval in lielgiuni (Hainaut), 

 monographed by Marty; and the small scat- 

 tered floras in the Thanet sands (gres de Ver- 

 vins, etc.) studied by Watelet and recently 

 revised by Fritel of the Paris Museum. None 

 of these floras are extensive enougli for de- 

 tailed comparisons with the Wilpox. Sucli 

 comparisons as are possible show that the Wil- 

 cox is younger than the Montian or the Thane- 

 tian, whose floras are more similar to those of 



tlie early Eocene of the western interior region 

 of tlie United States and are at least partly 

 represented in the emba>nnent area l)y the de- 

 posits of tile Midway formation. The one 

 feature of noticeable pariiHelism between these 

 early Eocene floras of Euroj)e and tiiat of the 

 WUcox is the abundant and strikingly similar 

 species of DryopliyUum in eacli. 



The next succeeding stage of the European 

 section is the Sparnaciaii, which contains 

 fossil plants in the "argile plastique" and the 

 "lignites du Soissonnais" of the Paris Basin. 

 The old work of Wat(^let has recently been 

 revised by Fritel, and tiiougli the flora is 

 still relatively smaU (less tliau 150 species) 

 it shows resemblance to the Wilcox in species 

 of Asplenium, Taxodium (identical), Sabalites, 

 Ficus, Laurus, Cinnamomum, Aralia, and 

 Sapotacites. The Woolwich and Reading 

 beds of West Kent, Surrey, and Sussex, in 

 England, of this age, contain a mostly un- 

 describcil flora of somewhat more temperate 

 facies than that of the Wilcox, though it 

 afl'ords comjjarable forms in the genera Lygo- 

 dium, Asplenium, Ficus, Laurus, Aralia, and 

 Sabalites. I regard the WiJcox as partly the 

 equivalent of the Sparnacian, although the 

 evidence for this correlation can not be con- 

 siilered conclusive. The succeeding stage of 

 the European section, the Ypresian, yields an 

 extensive flora. Though this flora is not very 

 rich in the gres de BeUeu of the Paris Basm 

 (150 species), it is very representative m the 

 pyritized seeds and fruits of tlie London clay 

 on the Isle of Sheppey and in the pipe day 

 of Alum Bay on the Isle of Wight. 



The flora of tlie gres de Belleu has com- 

 para])le species of Lygodium, Sabalites, Can- 

 nophyllites, Juglans, Myi-ica, Artocarpidiuin, 

 Ficus, Anona, Persea, Laurus, Dryophj^Uum, 

 Cercis, Banisteria, Cinnamomum, Sterculia, 

 Acacia, Sapotacites, Banksia, Anacardites, 

 ApocynophyUunr, Clu-ysophyUum, DiospjTos, 

 Magnolia, Grewia, Terminalia, Eugenia, Gle- 

 ditsia, Ciesalpinia, Entada, and Lcguniinosites. 



Ficus scJiirnperi is much like Ficus cuspidata 

 Watelet, Oreodaphne mississippiensis is repre- 

 sented by Laurus attenuata Watelet, Mespi- 

 lodaphne coushatta by Persea regularis Watelet, 

 ('(I'cis wilcoxiana by Cercis deperdita Watelet, 

 (ilpditsiopJiyJIumfructiiosum. by Acacia hrongni- 

 arti Watelet, OleditsiopJiyllum entadaformis by 

 Entada dubia Watelet, Banisteria pseudolauri- 



