FROM THE TERTIARY OF THE STATE OF MISSISSIPPI. 



423 



Red shale. 



There is not any difference of form between this seed and those of our common Pappaw 

 (Asimina triloba, Dun.). But it would be over-presuming indeed, to try to identify species 

 from a mere flattened seed, half imbedded in the stone. In the same fruit, the seeds of 

 the Pappaw vary greatly in form and size ; they arc nevertheless generally undulated or 

 wrinkled across, a character which is not seen in the fossil. 



30. Phtllites truncatus, Spec. nov. PI. xvii, Fig. 9. P. foliis oblongis, lanccolatis, integris, undulatis, 

 basi in petiolo brevi truncato decurrentibus; norvis seoundariis gracilimis, distantibus, camptodrouiis. 



Red shale. 



The leaf is oblong, with undulate entire borders, apparently lanceolate pointed, nar- 

 rowed to the petiole or to the base of the medial nerve, where it is slightly decurrent and 

 abruptly cut, forming a short winged-like petiole. The secondary nerves arc indistinct 

 and very slender. Prof. Charles Gaudin, in his 4th Memoir of Contributions a la flore 

 fossile llal.ienne, has published, page 23, PI. v, Figs. 6 and 7, two leaves of the Post ter- 

 tiary, which he considers as Viburnum tinus, S., now living in the South of France. By 

 their form and nervation these leaves appear exactly similar to ours. 



Is it possible now, from the small number of fossil plants described above, to draw any 

 conclusion concerning their geological distribution? And first, do the plants by their 

 analogy indicate synchronism between the various strata where they have been found 1 



As it is remarked in the introduction, our leaves are imbedded, either in a red, lami- 

 nated, ferruginous shale, of a fine-grained compound, in whose layers the impressions of 

 leaves are horizontally marked and distinct, though their substance is totally destroyed ; 

 or on a soft white clay, easily cut with the knife, where the impressions are equally dis- 

 tinct and horizontal, and the substance of the leaves also destroyed ; or on a yellowish 

 coarse sandy clay, casually veined with a soft white clay like the former. In this matter 

 the leaves are well defined, their substance is more or less preserved ; but they are mostly 

 distorted or folded, as if they had been transported with the materials in which they are 

 imbedded. One of our species only is on a coarse brownish sandstone, whose compound 

 is unlike any of the former; the substance of the leaf is fully preserved. 



According to Prof. Ililgard's statements, as much as can be seen from the disposition 

 of the plants-bearing strata, there is not any great difference in their horizontal stations. 

 He acknowledges the lithological characters as being heterogeneous, but he accounts for 

 this by the interposition of materials of various kinds, especially of ferruginous sand mod- 

 ifying the nature of underlying clays, and by the various modes of transportation and 

 deposition of these materials. " As for the red shales," he says, in a letter on the subject, 



