136 



LOWER EOCENK FLORAS OF SOUTHEASTERN NOHTII AMERICA. 



toward the close of tho Oligocene, not t<> im-n- 

 tion the evidence derived from still older floras 

 of more remote liotaiiic afluiities, wlierever 

 fossil floras are found, from tlie Equator to the 

 re<;ion within the Aretie Circle, they show a 

 degree of uniformity wliicli proves tliat former 

 climates were secularly unlike those of to-day, 

 and it is ohvious that this floral evidence would 

 he eciually convincing if all the vast number 

 of fossil plants were simply called PhylUtes as in 

 Scldotlieim's day and no attempts were made 

 to determine their botanic aHinity. 



The student of fossil floras is naturally more 

 sanguine and entliusiastic in predicting former 

 physical conditions than perhaps is warranted 

 by the facts. \Alien, however, a common Up- 

 per Cretaceous flora can be traced from Texas 

 to Greeidand or when we find in the Eocene 

 such unmistakable forms as leaves of Arto- 

 carpus, fruits of Engelliardtia, and nuts of the 

 nipa pahu associated witli forms as cliaracter- 

 istic as ferns of the genus Acrostichum, aU 

 extending almost across the Temperate Zone 

 m both the Eastern and Westei'n liemispheres, 

 it would seem that the burden of proof that 

 climates were not very different from tliose of 

 to-day rests with the physicist and not with 

 the paleobotanist. 



In a short paper ' read before the American 

 Philosopliical Society in 1911 a few of the 

 features of the Wilcox environment were 

 pointed out and in the present discussion of 

 the botanic character as well as in the system- 

 atic description of the Wilcox flora it has been 

 inexpedient to refram from mentioning certain 

 ecologic features in tlie discussion of tlie ele- 

 ments of the flora. The table of general dis- 

 tribution at the end of the discussion of corre- 

 lation indicates in a general way the most 

 similar living species with their habitats, and 

 the systematic descriptions abound in com- 

 parisons with recent forms, so that it is inad- 

 visable to give detailed lists here. It may be 

 noted that the Wilcox plants, almost without 

 exception, are plants whose modern repre- 

 sentatives inhabit tlie warmer parts of the 

 earth. There is not a single strictly temperate 

 type in the whole assend)lage, the nearest ap- 

 proach to such types being the genera Juglans, 

 Myrica, MagnoUa, Cercis, Ilex, Nyssa, and 



•Berry, E. W., A study of the Tertiarj'florasof the Atlantic and GiUf 

 Coastal Plain: Am. Philos. Soc. Proc, vol. 50, No. 199, 1911. 



Fraxinus, and in all these or in closely related 

 genera there are existing tropical forms. None 

 of them extent! beyond the warmer parts of tlie 

 Temperate Zone and some, as Juglans ami Frax- 

 inus, indicate in their compound leaves their 

 tropical ancestry, as was first pointed out by 

 Grisebach. Tlie ferns are all tropical types, 

 and their relative unimportance in tlie Wilcox 

 flora furtliermore indicates that the major part 

 of this flora is a strand flora. This character 

 is shown more especially by forms like the 

 nipa i)alm, which never grows outside of tidal 

 marshes, and by Conocarpus, Laguncularia, 

 and Avicennia, which inhabit like regions. 

 Coastal marsh or lagoon plants like Canna, 

 Trapa, and Sabalites, and the large number of 

 strand types that inhabit beaches or the jungle 

 behind the beach ridges or dunes add to this 

 evidence. The more striking of these genera are 

 Myrica, Artocarpus, Ficus, Coccolobis, Pisonia, 

 Aiiona, Capparis, Clxrysobalanus; several genera 

 of Lauraceje, Apocynacese, Sapotacese, and Le- 

 guminosfe; Fagara, Cedrela, Drypetes, Meto- 

 pium, Ilex, Celastrus, Sapindus, Dodouffia, 

 Reynosia, Rhamnus, Myrcia, Eugenia, Laguncu- 

 laria, Combretum, Terminalia, Cordia, Cithar- 

 exylon, Exostema, and Guettarda. 



It needs but a slight acquaintance with the 

 existmg Antillean flora or that of the Florida 

 Keys, or in lieu of actual acquaintance a peru- 

 sal of the few ecologic discussions of the flora 

 of the American Tropics or even of Schimper's 

 classic Indo-Malayaii strand flora, to see at 

 once that the general facies of the Wilcox 

 flora is overwhelmingly that of a strand flora, 

 some of the elements of which indicate that 

 they grew on the sandy beaches, others in 

 muddy tidal flats, others between or behind 

 dunes or beach ridges, and others in estuary 

 bayous or marshes. Such a Wilcox bayou, 

 subsequently converted into a small coal basin, 

 is that at Hoyt Station, Wood County, Tex., 

 which winds across the strike of the Wilcox 

 beds and has a diameter of half to three-quar- 

 ters of a mile and an exposed length of 3 

 miles. ^ None of the forms can certainly be 

 considered iidand or upland types. Even 

 genera like Banksia, which is not usually 

 considered a coastal type, furnishes in the ex- 

 isting flora Bankna imin/inafa Cavanilles to 

 the coastal sand dunes of South Australia 



2 White, David, Bur. Mines Bull. 38, p. 12, 1913. 



