129 



Niedershoena. Among the dicotyledonous vegetable remains, we find seeds 

 of Myrica of the same form as those described by Heer from Qnedlinburg ; 

 leaves of Querent primordialis related to Phyttites Geinifzianus of the Quader- 

 sandstein of Silesia; an Ara/ia and a Protophyllum, represented by analo- 

 gous forms in the flora of Moletin ; and, in relation to the Cretaceous flora of 

 Niedershoena, there is still to record, Ficus halliana compared to F. Geinitzi, 

 and Celastrophyttum ensifolium distantly related to C. lanceolatuin. 



This is sufficient to prove, relatively to our present knowledge, at least, 

 the truth of the assertion that the flora of the Dakota group, without affinity 

 with any preceding vegetable types, without relation to the flora of the Lower 

 Tertiary of our country, and with scarcely any forms referable to species 

 known from coeval formations of Europe, presents in its whole a remarkable, 

 and as yet unexplained case of isolation. 



§ 11.— Conclusion. 



After the printing of the last pages of this memoir, I have received, by 

 the kind liberality of the authors, the third and last volume of W. P. Schimper's 

 great work on vegetable paleontology,* and a very important memoir on the 

 fossil plants of Gelinden, (Belgium,) by Count Saporta and Dr. Marion. 

 Both these volumes expose documents of importance in regard to the Cretace- 

 ous floras of Europe, and, by correlation, to that of the Dakota group. 



The geological station of the clay-beds bearing plants of Gelinden is 

 referred by the Belgian geologist, Dewalque, to an inferior member of a 

 group of strata intermediate to the Cretaceous and the Tertiary, or forming 

 the lowest division of the Tertiary, under the name of Period Paleocene.f 

 This geologist divides this group into the following stages: at the base, 

 the Limestone (calcaire) of Mons ; above it, the Heersien system; then, in 

 ascending, the Landanien, (inferior and superior;) the Ypresien, (inferior and 

 superior;) and the Paniselien. The lowest stage, the Limestone of Mons, 

 is generally considered as the lowest Tertiary of Europe. Till now, no 

 remains of fossil plants have been discovered in it. The Ypresien corresponds 

 to the London clay ; the clay-beds of Gelinden are placed in the Heersien 

 system, by the authors of the flora.f 



* Traitc" de pal<?ontologie vegetale on la limn dn uioude priinitif, Ac 



tin Schimper's work the Tertiary is divided into five periods: 1st, Paleocene; 2d, Eocene; 

 lid, Oligocene ; 4th, Miocene; 5th, Pliocene. 



X Essai surl'6tat de la vege'tation a l'^poque de marnes heersienues do Gelinden, by Count Saporta 

 and Dr. A. F. Marion, pp. 8-11. 



17 L 



