FLOKA OF THE WOODBINE SAND AT ARTHURS BLUFF, TEX. 



155 



valley thin toward the south or are replaced 

 by different lithologic facies which have re- 

 ceived other names and whose equivalence 

 has not been determined. No representative 

 of the Woodbine has been recognized in central 

 Texas, where, according to Stephenson,' its 

 age equivalent is absent or "lies in the rela- 

 tively thin sediments that compose the Buda 

 limestone, a supposition which seems highly 

 improbable and which has no basis of laiown 

 facts." A third alternative which I regard 

 as more probable than the two advanced by 

 Stephenson is that the leaf-bearing sands of 

 Red River which are referred to the lower 

 Woodbine are the time equivalent of what is 

 called Eagle Ford in the Austin section. 

 Either Woodbine time is represented there 

 by the Buda limestone, which Stephenson 

 states is highly improbable, or it is repre- 

 sented by a break in sedimentation, which 

 seems to me equally improbable, or it is repre- 

 sented by the lower part of the Eagle Ford 

 of that section. 



FAUNA. 



The fauna of the Woodbine, which comes 

 from the upper part, or the Lewisville marine 

 member, is not extensive, but certain species 

 are individually abundant at some localities. 

 It comprises an almost unique assemblage of 

 shallow-water forms as iilentified by Cragin. 

 including the following: 



Area galliennei var. tramatensis Cragin. 

 Ostrea soleniscus Meek. 

 Modiola filisculpta Cragin. 

 Aguileria cumminsi White. 

 Cytherea leveretti Cragin. 

 Trigonarca siouxensis (Hall and Meek). 

 Turritflla renauxiana D'Orbigny. 

 (.'(•rithiiim tramatensis Cragin. 

 Cerithium interlineatum Cragin. 

 Pteria salinensis White? 

 Natica humilis Cragin. 



It contains also a considerable number of 

 additional forms including ammonites, not yet 

 determined. It is unfortunate that no ade- 

 quate study of the Woodbine faima has ever 

 been made. 



FLORA. 



The flora of the Woodbine sand described in 

 the following pages amounts to only 43 species. 

 It is hence inadequate for a correct estimate 



« Stephenson, L. W., V. S. Geol. Survey Prof. Paper 120, p. 145, 1918. 



of its botanic facies, and the absence of forms 

 normally present in beds of equivalent age 

 may, with much probability, be attributed to 

 their lack of discovery in the Woodbine, for 

 as far as it goes it is a perfectly normal assem- 

 blage of forms such as would l)e expected at 

 this horizon. There are no known ferns or 

 lower plants present, presumably because of 

 the coarseness of the sediments and the 

 trituration to which most of the plants have 

 evidently been subjected. 



Only two g3annosperms are represented, a 

 Podnzamites and a Brachyphyllum. In this 

 respect the Woodbine flora is more like the 

 Dakota flora than it is like the corresponding 

 floras of the Atlantic Coastal Plain, in which 

 C(mifers are usually abundant individually and 

 varied specifically. No monocotjdedonous an- 

 giosperms have been recognized in the Wood- 

 bine, and this lack, like that of the ferns, is 

 probably to be attributed to macerating and 

 triturating water action. 



The dicotyledons, which comprise 41 of the 

 4.3 identified forms, represent .31 genera in 21 

 families and 1.5 orders. They are well scat- 

 tered among the families usually represented 

 in Upper Cretaceous floras. Elements that 

 are conspicuous by their absence when the 

 Woodbine flora is compared with the Tusca- 

 loosa flora of the eastern Gulf area, for ex- 

 ample, are the numerous species of figs and 

 magnolias, for there are only two of each of 

 these types in the Woodbine, and one of the 

 figs is a Dakota sandstone species and not a 

 Coastal Plain species. Other notable absen- 

 tees are Menispermites. Banldiria, Lirioden- 

 dropsis, Leguminosites, Celastrophyllu7n, Gre- 

 wiopsis, Ptfrospfr mites, Sapotacifcs, and other 

 less significant genera. The genus Cdas- 

 trophyllum is especially abundant in the Tus- 

 caloosa, in which 12 species have been recog- 

 nized, and it is almost equally abundant in the 

 Raritan formation. 



No genus is represented in the Woodbine by 

 more than two species except the form genus 

 CarpoUthus. The largest family is the Laura- 

 ceae, with eight species; no other family has 

 more than tlu-ee species, and only two families, 

 the Salicaceae and Magnoliaceae, reach that 

 number. Similarly the largest order is the 

 Thymeleales, with eight species, and the only 

 order that approaches it in size is the Ranales, 

 with five species. 



