44 



rials, it is certain that this flora is still very imperfectly known in its essential 

 characters and its diversified forms. 



A valuable assistance has been given me in the revision of this memoir, 

 ami since the engraving of the plates, by Count Saporta, of Aix. An exami- 

 nation of the first proofs of the plates suggested to him, on the relation of 

 some leaves, important remarks which have been used for the distribution of 

 the groups and the limitation of some genera. The thankful acknowledg- 

 ment of this cordial assistance is as pleasant to me as has been the exchange 

 of views and the intercourse with a paleontologist of so high a standing and 

 so justly celebrated. 



CKYPTOGAMOUS PLANTS. 

 Thallophytes. 



ZONARITES DIGITATUS, Brgt., PL i, Fig. 1. 



Frond flat, membranaceous, dicbotomous, branching in an acute angle of divergence ; divisions as 

 broad or broader than the main axis, linear, entire, obtuse, sliglitly enlarging upward. 



Fucoidcs digitatus, Brgt., Hist. d. Veg. foss. p. 69, PI. ix, Fig. 1. — Zonarites 

 digitatus, Geinitz, Dyas., PI. xxvi. — Lesqx. in Haydcn's Report, 1872, 

 p. 421. 



Our specimen is less complete than the one figured by Bronguiart. 

 It is broken on one side, and merely repi'esents two of the divisions of the 

 plant. These, one cent, broad, slightly enlarging upwards, diverging under 

 an angle of 20°, are apparently of thin membranaceous texture, merely 

 marked by the irregularities of the surface of the calcareous clay over which 

 the plant is preserved. No difference is observable between this and the 

 European form, except in the slightly broader size of the divisions. The 

 main axis has the same character as the branches, slightly enlarging from 

 the base upwards. 



The relation of these remains has not yet been positively ascertained. 

 Schenk, in Paleont. xi, p. 301, compares it to Cyclopteris digitata, Brgt., 

 a fern of the Oolithe. Schimper, Pal. Veget., p. 186, rejects this opinion 

 from anomaly of characters, and would consider it as referable to the genus 

 Jean-Paulia, Ung., which, too, represents species of uncertain affinity related 

 to ferns. The association of these fossil remains with those of animals of 

 deep marine water, large Am??wnites, Baculites, Inocera?ni, is a sufficient indi- 

 cation of their submarine origin, and if they represent a plant it is truly a 



