2-4 PROCEEDINGS OF WASHINGTON MEETING. 



The lower members of the Trias corresponding to the Buntersandstein and 

 Muschelkalk of Europe, if present at all in the United States, are not believed to 

 have furnished any of the fossil plants that are referred to that system. In fact, 

 although the Triassic beds of this country have in some places a great thickness, 

 and although there are indications that those of certain localities occupy a some- 

 what different position from those of others, still, taking all the evidence into the 

 account, it seems probable that not only all the plant-bearing strata, but also all the 

 rocks which are known as Triassic within the limits of the United States, belong 

 near the top of the system and represent the upper Keuper, or perhaps the upper- 

 most of them may correspond to the Rhetic of the Old World nomenclature. 



As the true Permian is scarcely found within our borders, it will be perceived 

 that between our rich plant-bearing Carboniferous formation and the next higher 

 deposits carrying vegetable remains a wide chasm exists, measured by an immense 

 period of time. It is therefore not to be expected that any traces of the Paleozoic 

 flora will be found in the comparatively recent deposits of the upper Trias. Such, 

 indeed, is the case, so far as we now know these floras, and we have to regard these 

 later deposits as the beginning of a new era in the history of plant life. 



It is true that Rogers, Bunbury and others of the earlier authors who described 

 the fossil plants of the Richmond coal field supposed that they had found speci- 

 mens of Lepidodendron, Sigillaria and Catamites ; but it is now known that this is not 

 the case ; that the supposed lepidophytes belong to the coniferre, and that the alleged 

 Calamiles was a gigantic Equisetum. Specimens of this last were sent to Brongniart, 

 and it was upon his authority that they were referred to Catamites (C. suckowii) ; 

 but Brongniart himself expressed doubts in regard to their relation to Calamites, 

 and it may be worth our while to hear what he says on that point. He made the 

 American specimen to constitute a variety of that species, and on this he remarks 

 as follows : 



" La var. dont la surface externe est assez mal eonservee, se rapporte cependant a cette espece 

 par sa forme generate et par la termite de l'eeorce. Les cotes sont seulement plus convexes, ce qui 

 pent tenir a une moindre compression ; car ces tiges, qui etaient probablement verticales, parais- 

 sent avoir ete comprimees dans le sens de leur longueur, et presentent des replis nombreux qui 

 semblent indiquer combien leurs parois etaient minces et flexibles. Cet echantillon est meme fort 

 remarquable sous ce rapport, et prouve que ces tiges etaient fistuleuses comme celles des Equisetum 

 vivans."* 



This species, which is the Equisetum rogersi of Fontaine, perhaps comes the 

 nearest to the connecting link between the Carboniferous and the Mesozoic of all 

 the American forms, but there is no doubt of its generic distinctness from Calamites. 

 It is possible that when the palissyas and other conifers of the Trias are better 

 known a close relationship will be found to exist between them and some of the 

 allied strictly Permian conifers ; but upon this no important conclusions can now be 

 based. The Triassic flora is also found to be almost as completely cut off from the 

 floras that are known in the United States above that horizon as they are from 

 those below it. If any distinctly Jurassic strata exist within our borders they are 

 not as yet known to carry fossil plants, and the next higher horizon at which these 

 are found is that of the Potomac formation of Virginia and Maryland, or the per- 

 haps equivalent Kootanie deposits of the great falls of the Missouri and the Trinity 

 division of Texas. These, appearing to be nearly of the same age, ought all to 

 belong to the lower Cretaceous. 



•Histoire des Vegetaux fossiles, vol. i, 1828, p. 126. 



