340 MESOZOIC FLORAS OF UNITED STATES. 



member occiir there also. The plant, Frenelopsis varians, found in both the Arkan- 

 sas and the Texas beds, is a peculiar one, and is so strongly characterized that it 

 can not be mistaken. 



Dr. Johannes Felix collected from Neocomian strata of Tlaxiaco, 

 Mexico, certain apparently jointed stems closely resembling those found 

 in the Trinit}^ and Glen Ptose beds, which were described and figured in 1893 

 by Dr. A. G. Nathorst," who considered them a new genus which he named 

 Pseudofrenelopsis, the species being named P. Felixi. Nathorst, how- 

 ever, had not seen Professor Fontaine's paper on the Glen Rose flora, 

 which appeared about the same time as the work of Felix and Lenk, but he 

 regarded the form as generically the same as the Frenelopsis parceramosa 

 of Fontaine from the Potomac formation. A comparison of his figures, 

 however, indicates that the Mexican plant is different from either the 

 Virginia or the Texas-Arkansas form, and the last named is certainly 

 jointed, and therefore, according to Nathorst, a true Frenelopsis. 



I have not included the Tlaxiaco flora in this paper, although belong- 

 ing to the Lower Cretaceous of North America; I will therefore add that 

 besides the Pseudofrenelopsis Felixi, Nathorst describes coniferous twigs 

 which he compares with Sequoia ambigua Heer and S. Reichenbachi (Gein.) 

 Heer. 



The Trinity l^eds of Arkansas have yielded one other vegetable form 

 that has not yet been mentioned, because, although collected by Mr. Hill 

 in 1888, it was not described till 1895. The material in which it occurs 

 was placed in Doctor Knowlton's hands, and this form is mentioned in 

 a letter from the latter to Mr. Hill, which was appended as a footnote 

 to the chapter on the paleontology of the Trinity division (Chap. XIII, 

 p. 152) of the Annual Report of the Geological Survey of Arkansas, Vol. 

 II, in which Doctor Knowlton says: 



There was a very interesting thing in some of the clayey material. It was 

 thickly filled with stems, as you may remember. I selected a few of them, boiled 

 them out in nitric acid, and mounted them in Canada balsam, when the structure 

 was brought out most clearly. It is something new, evidently, and so far as I could 

 find in the time I was able to give the subject, is undescribed. I have not decided 

 what to call it, and indeed a mere description, without accompanying plates, would 

 be of very little scientific value. 



" Pflanzenreste aus dem Neocom von Tlaxiaco, by A. G. Nathoi-st in Beitrage zur Geologie und Paliion- 

 tologie der Republik Mexico, von J. Felix und H. Lenk, II. Theil, Leipzig, 1893, pp. 51-54. See p. 52, figs. 6-9. 



