GEOLOGICAL SURVEY OF THE TERRITOEIES. 303 



in the middle into a short lobe, narrowed upward to an obtuse point, 

 caneate to the base, with borders undulately denticulate 5 secondary 

 veins, oblique, straight, the lower pair ascending to the point of the 

 lobes, much divided -, nervilles, simple, continuous, deeply marked. 



Platanus Heerii, §29. '?iO'?7. A species represented by many good 

 specimens. Leaves, round in outline, with short, obtuse, lateral lobes, 

 and an obtuse, short point ; borders entire, wavy, or obtusely, distantly 

 dentate, passing in a broad angle, even by a rounded curve toward the 

 petiole, on which they descend in decurring to it, forming a short wing. 

 Petiole apparently short, one inch long, as seen in one of the specimens. 

 The basilar wing is marked with one or two pairs of horizontal, narrow 

 veinlets, running along the borders; the first pair of secondary veins 

 above them is thick, straight, oblique, much divided in tertiary and 

 quaternary veinlets, which, like the febrilles, are dee^ily marked. Tex- 

 ture, thick; surface, smooth; areolation of P. occidentalis. As in this 

 species also, the second pair of lateral veins is at a greater distance 

 from the first. 



Sassafras obtusus, sp.nov. A true sassafras, to which is referable 

 the leaf i)ublished in Am. Jour. Sci., vol. XLY, p. 94, under the name of 

 Fopulites Salishuriwfolia, Lsqx. 



Phyllocladus subtntegrifolius, Lsqx., {loG. cit, p. 92.) A larger 

 leaf tban the former described ones, obovate, undulate on the borders 

 from the middle upward, obtusely x^ointed, with same nervation. 



IL— EEMAKKS OK THE ORETAOEOIJS SPECIES DESCRIBED 



ABOVE. 



The above enumeration mentions fourteen species of fossil plants 

 from our Cretaceous formations. It is a small group, indeed ; yet, on 

 the whole, an interesting and valuable contribution to our knowledge 

 of the Cretaceous flora of our continent. Seven of these species are 

 new ; three Pterospermites, the first American representatives of this 

 group, excepting, perhaps, one species of the genus Credneria, considered 

 by some authors as allied to it, though not yet satisfactorily deter- 

 mined.* The Fterospermites re-appear in the Tertiary of our con- 

 tinent, with analogous characters, at least. P. quadratus^ Lsqx., re- 

 sembles, especially by its nervation, P. dentatus, Heer, from Mackenzie, 

 while P. Haydeni, Lsqx., is, by its size, the form of its leaves, and their 

 nervation, a near relative of P. spectaMliSj Heer, from Greenland. The 

 affinity of typical forms is remarkable, on account of the difference of 

 latitude or of the geographical habitat and the geological station of these 

 plants. The fourth new species, Magnolia enstfolia^ Lsqx., is allied by 

 some characters to Magnolia crassifoUa, Gopp., from the Tertiary of Sile- 

 sia; while the fifth, the fine Platanus Heerii, Lsqx., has, for represent- 

 ative in our Tertiary, Platanus aceroides^ Gopp., and Platamis GuiUclmw, 

 Gopp., two intimately related forms. Therefore, on seven new species 

 of the Cretaceous described here, five have a marked Tertiary'- facies, 

 while, at the same time, three of them, at least, have what may be called aii 



* Our Ptcrosjjcrmites have analogy of form and nervation with Ptcrospcrmuvi, Schreb., 

 a genus of the Ihittueriacew. Heer, in his Fl. Ter. Helv., has i)ublishe(l seeds refcrablo 

 to the same kind of xdants. There is, therefore, scarcely any doubt al)out the rehition 

 of these leaves. It is different with Credncria. Its place is, as yet, un(h>.lined. Though 

 resembling by some of its characters, especially by size and general nervation, the 

 leaves of somo rierospermites, their form, their basilar nervation, and the mode of at- 

 tachment of the petiole are different. We have from our Crt'taeeons oC Nebraslca one 

 Crcdneria, (C. iccowfrnwa, Lsqx.,) apparently identical with C. macrophyllayllecv, of tho 

 Quadersandstoin or Upi>er Cretaceous of Moletein, Moravia. 



